I am in the process of moving a mail system from Sendmail to Postfix. The
system in question currently handles a small number of domains in a virtual
configuration. I am attempting to replicate the existing functionality with
Postfix’s virtual domain capability. The specific configuration to be used
is the second example on the Postfix Virtual Domain Hosting Howto: Separate
Domains UNIX System Accounts. This method has been selected as it matches
what exists with the current system. At some point I will change this but
for the migration I want to eliminate as much disruption as possible.
The configuration is fairly straightforward and I’ve copied the appropriate
files from the Sendmail configuration to the Postfix configuration and all
seems to be operating as expected with one exception. If the UNIX user
account on the right hand side of the virtual mapping doesn’t exist Postfix
doesn’t appear to reject the user. Using the example virtual file from the
howto:
6 [email protected] postmaster
7 [email protected] joe
8 [email protected] jane
If the UNIX user "joe" does not exist in the UNIX password file mail sent to
"[email protected]" is accepted. With the Sendmail configuration both the
left hand side (the virtual e-mail address) and the right hand side (the
UNIX user that is the destination) need to exist or Sendmail will return a
user unknown. Is the normal behavior of Postfix's virtual configuration
using UNIX system accounts to accept an e-mail as long as it exists on the
left hand side of the mapping table? In practice every alias on the left
would map to a real account on the right. But occasionally mistakes happen
and a UNIX account may not exist (which would need to be corrected). I don't
see this as being a problem but wanted to confirm the behavior. If this is
normal then I've configured it correctly. If not then I've done something
wrong (though I don't know what that might be as this appears to be fairly
straightforward...thus if this is not the expected behavior I'm open to
troubleshooting suggestions.
