I'm looking for a way to define multiple hostnames - a specific hostname for each domain I'm running. That means for example I have configured mail domains and mails accounts for domain1.com, domain2.com and domain3.com. Right now, all mails will be sent with the fqdn of the mailserver. In this case its server.domain1.com. But I don't want to handle it this way. If mails will be sent from a domain2.com account, the hostname which will be sent should be server.domain2.com. Also in case of a mail from domain3.com, the hostname which will be sent should be server.domain3.com. Is this possible and how can this be achieved?
That should be possible, but you need a separate IP address for each domain then for postfix to handle it like that.
Well Till, I can make a separate IP address. What are the necessary steps? I've also found some threads (serverfault.com, linuxquestions.org), but none of them make me happy! - Ok, I see I'm not able to post it, because I'm new.
I guess you have to define each IP in master.cf for smtp instead of using a global 'smtp' listener line and then specify a different hostname for each IP. But I haven't used such a setup yet, so there might be more things to change.
Yes, that's basically it, combined with a sender_dependant_default_transport_maps for outgoing. See https://www.howtoforge.com/community/threads/different-ip-for-email.70582/
