The server computer has 2 IP addresses: 192.0.0.1 and 192.0.0.2.
The Server Main Domain is company.com, and the secondary Domains are
client1.com and client2.com.
The DNS A-records for company.com is pointing to the IP address 192.0.0.1,
the A-record for the client1.com points to a dedicated IP address 192.0.0.2,
while the A-records for the client2.com domain point to the same "main" IP address 192.0.0.1.
Each domain has an account info.
Three users configure their clients to access an account info,
but they specify different names in their "server" settings: the first
user specifies company.com, the second - client1.com, and the third user specifies client2.com.
When the first user starts her mailer:
- The client application takes the specified "server" setting company.com, and
it uses the Domain Name System A-records to resolve (convert) that name to the IP address 192.0.0.1.
- The client establishes a connection with that address (which is one of 2 addresses of
the Server computer), and it passes the user name info.
- The Server detects a simple user name info and detects that this connection
is established via the Server address 192.0.0.1.
- The Server detects that this IP address is assigned to the Main Domain, so it adds the
Main Domain name company.com to the specified simple name.
- The Server gets the correct full account name info@company.com.
When the second user starts its client application:
- The client takes the specified "server" setting client1.com, and
it uses the Domain Name System A-records to resolve (convert) that name to the IP address 192.0.0.2.
- The client establishes a connection with that address (which is one of 2 addresses of
the server computer), and it passes the user name info.
- The Server detects a simple user name info and detects that this connection
is established via the server address 192.0.0.2.
- The Server detects that this IP Address is assigned to the client1.com secondary Domain,
so it adds that Domain name to the specified simple name.
- The Server gets the correct full account name info@client1.com.
When the second user starts its client application:
- The client takes the specified "server" setting client2.com, and
it uses the Domain Name System A-records to resolve (convert) that name to the IP address 192.0.0.1.
- The client establishes a connection with that address (which is one of 2 addresses of
the Server computer), and it passes the user name info.
- The server detects a simple user name info and detects that this connection
is established via the Server address 192.0.0.1.
- The Server detects that this IP address is assigned to the Main Domain, so it adds the
Main Domain name company.com to the specified simple name.
- The server gets the incorrect full account name info@company.com.
This happens because the client application (usually - an old POP or IMAP mailer, and FTP client, etc.)
has not passed the information about the "server" name from its settings,
and the only information the Server had was the IP address.
In order to solve this problem, the third user should specify the account name as
info%client2.com, not just info. In this case, when this users starts the
client application:
- The client takes the specified "server" setting client2.com, and
it uses the Domain Name System A-records to resolve (convert) that name to the IP address 192.0.0.1.
- The client establishes a connection with that address (which is one of 2 addresses of
the server computer), and it passes the user name info%client2.com.
- The Server detects a full user name info%client2.com and it does not look at the
IP addresses. It just converts the % symbol into the @ symbol.
- The Server gets the correct full account name info@client2.com.
Note: most FTP clients work in the same way as the POP/IMAP mailers do, so FTP users are required to
supply qualified Account names unless they connect to an IP Address assigned to their Domain.
Note:the MAPI Connector always sends a quialified Account Name: if users specify names without
the @ or % signs, the Connector adds the '@' sign and Server Name setting value to the
specified account name.