I have a fully working cyrus+sendmail mail server hosting all users for foo.com. Company foo has been acquired by company bar and it has been decided that bar.com is the new domain of choice. The administrator of bar.com has added a pile of redirects to send various user@bar.com addresses so they come up to my server at foo.com. My users have changed their From: addresses to user@bar.com and we have a basic working system.
However, if one user in former company foo mails another user in the same office their mail now goes offsite to bar.com's mail server and is then redirected back in again, which works but is bad for bandwidth.
Ideally I'd like to teach sendmail that a subset of bar.com users are now local. However if I try this in the /etc/aliases file, I get the warning "cannot alias non-local names".
Has anyone got any better ideas how to do this- or a better suggestion as to where I should ask this question again?
-- Cheers,
Tony