Tug Williams via linux wrote on 2026-03-24 08:51:
Minor semi-tangent. When I decided to add a new domain, the internet
first encouraged me to change
myhostname = mydomain1.com
to
myhostname = mail.mydomain1.com
The justification seemed sort of sensible, but I wonder whether the
faffing was worth it. Is this "correct" or "who cares", given I doubt
I will ever have multiple IP addresses, so don't need to distinguish
web sites from email servers?
It's probably more of a Best Practices but not Essential. Postfix docs say:
> $myhostname <https://www.postfix.org/postconf.5.html#myhostname> is
used as a default value for many other configuration parameters.
but they do not specify which those other parameters are, so... whatever
hostname is shown by, say, `hostnamectl` is a good idea.
I'm using linux system accounts, and had administered catchall via
/etc/postfix/virtual
user [ at ] mydomain1 [ dot ] com user
@mydomain1.com user
Okay, virtual is good...
postconf -n (heavily snipped)
mydestination = localhost, localhost.$mydomain, mydomain1.com
If using virtual transport delivery, note this:
> NEVER list a virtual MAILBOX domain
<https://www.postfix.org/ADDRESS_CLASS_README.html#virtual_mailbox_class>
name as a mydestination
<https://www.postfix.org/postconf.5.html#mydestination> domain!
www.postfix.org
Postfix Virtual Domain Hosting Howto <#>
🔗 https://www.postfix.org/VIRTUAL_README.html#virtual_mailbox
<https://www.postfix.org/VIRTUAL_README.html#virtual_mailbox>
virtual_alias_domains = mydomain2.com
virtual_alias_maps = hash:/etc/postfix/virtual
/etc/postfix/virtual contains
user [ at ] mydomain1 [ dot ] com user
user [ at ] mydomain2 [ dot ] com user
user2 [ at ] mydomain2 [ dot ] com user2
@mydomain1.com user
@mydomain2.com user
/etc/postfix/virtual.db is generated
So, what I would look at is removing mydomain1.com from $mydestination
and then see what happens.
Probably not a complete answer, but hopefully a step in the right direction.
(Reviewing some of this, and the docs, and my main.cf files... I gotta
admit I kinda hate postfix sometimes.
I'm now thinking I need a deep-dive review of virtual_mailbox_domains,
virtual_mailbox_maps, virtual_mailbox_base, virtual_alias_maps,... It
all works, but I forget how & why.)