I want to setup a mailserver with a public DNS record. There are already some threads here in the forum, but the most relevant I could find is five years old (Postfix myhostname) and the bug report is closed (https://forge.univention.org/bugzilla/show_bug.cgi?id=30350).
My server admin book is telling me that it is very important, that
postconf myhostname will prompt the DNS registered fdqn. In UCS it is the local DNS fdqn - having the internal domain name in it (can be resolved also from public DNS).
The solution can of course go in different directions:
- don’t care to change local DNS name in the public sphere
- changing the myhostname setting in main.cf
The question is: what is - for security reasons as well as for system stability - the way I should go? As changing myhostname is not possible through a ucr registry entry. Perhaps telling the world the internal domain-name isn’t a big problem too?
Any thoughts on this are appreciated, kind regards