Best practice for Mail Gateway FQDN?

[rammwurst]

Incoming mails are forwarded through one of our routers to the proxmox mail gateway

Therefor it doesn't technically need to use any specific public FQDN - but could in theory be named whatever it wants to be, at least that has been the experience for the last few years

Now we have set it up fresh and came to thinking what the ideal hostname for the mail gateway would be.

Does it matter at all in our scenario? Would it conflict with anything if we gave it a public domain name?

 

[Stoiko Ivanov]

Put shortly the fqdn you set for your PMG is used in the following places which are visible when it sends receives mail (from the top of my head - so I might miss something):
* the smtp-banner contains it - some remote systems will not send mails if there is a mismatch
* it's the helo name the system uses - some (not many in my experience) receiving systems will not accept mail if there is a mismatch between
IP->helo_name mapping
* the name is usually visible in the received headers of each mail

In any case - if it worked in your environment until now with a internal name - I don't see why this should change all of a sudden

I hope this helps!