We are currently running a root server with Debian 6 and Plesk 10.4.4. We have some virtual hosts using one IP adress (shared) - e.g. example1.com - and another virtual host using a dedicated IP address (example2.com).
Is there a way to configure postfix to do the following
- Always use the IP address of the virtual host to which the e-mail account belongs (so that an e-mail from email@example.com will originate from the shared IP-Address and an e-mail from firstname.lastname@example.org will originate from the dedicated IP?
- Use different certificates for TLS for example1.com and example2.com?
If the latter is not possible: Could any problems arrive when using example1.com as certificate for example2.com users? Of course, example2.com users would have to configure their clients to use example1.com as the SMTP server name to avoid annoying security warnings. But if we still would be able to get the effect of the first point that would still be acceptable.