Courier-MTA as alternate mailserver
Most folks would be familiar with courier-imap as one of the pop/imap servers available for ISPConfig but not many folks have used the associated courier-mta (mail transfer agent) mailserver instead of postfix. I've used courier-mta for 10 years and only now just started using postfix because it's the only option with ISPConfig. I miss courier-mta so I am just wondering if anyone else using ISPConfig would like to see courier-mta as an alternate mailserver option?
The latest version of courier-authdeamon can use SQLite as a backend which I would find useful on a small VPS (postfix can too) but the most amazing feature of courier-mta is that it can use real vhosts on separate IPs. I mean totally separate domains can be delivered from courier-mta where the sending IP *AND* the initial EHLO hostname can be configured for an unlimited number of domains on the same host. postfix can kind of emulate this and send from a different IP on the same server but it can't provide a different EHLO hostname without running separate instances of postfix per virtual domain. A courier-mta vhost is completely transparent to the receiver, they cannot tell by looking at the delivered mail headers that this message came from a virtual host and SPF works perfectly.
This is quite useful, aside from "vanity" vhosts, in that if one clients mailserver gets blacklisted then it doesn't also blacklist all other clients on the same server. Plesk has a trick for doing this for exactly this reason but, as I mentioned, postfix still uses the EHLO hostname from the main server, not the vhost.
So fully independent multihosted mailservers of interest to anyone?