Local DNS Resolver and Error releasing spam

[dthompson]

Hi all,

I followed the article here:
https://forum.proxmox.com/threads/how-to-local-dns-resolver-for-proxmox-mail-gateway.41189/

And it seems to be working OK, but when I go and release a spam message, I get an error delivering to the end host.

If I switch back my resolvers back to my internal DNS servers, the emails are released properly. I've been trying to figure out what I am missing.

When I am using the local resolver, I am getting the following message delivered to me (not the end user)

<user@domain.com>: host 192.168.11.10[192.168.11.10] said: 553
5.1.8 Sender address <postmaster@mx.localdomain> domain does not exist (in
reply to MAIL FROM command)
Reporting-MTA: dns; mx.localdomain
X-Proxmox-Queue-ID: 90A64161D23
X-Proxmox-Sender: rfc822; postmaster@mx.localdomain
Arrival-Date: Tue, 16 Oct 2018 19:54:27 -0400 (EDT)

My resolvers in /etc/resolv.conf are
search: localhost
nameserver: 127.0.0.1

My hosts file looks like this:
127.0.0.1 localhost.localdomain localhost

I haven't changed it from the default, but I don't think I need to, but could be mistaken.

Can anyone shed some light on this for me? Ideally Id like to use each gateway as a local resolver, but this is causing me some issues delivering quarantined messages the the end user(s)

 

[heutger]

Hi,

I'm not completely sure, but I'm afraid it's because you set the search to localhost. I also use the name server 127.0.0.1 with unbound (bind9 had many problems), but I set the search domain to the domain of the system itself. I believe, the search domain on your internal servers is different and therefore mx.localdomain gets changed to mx.yourdomain.tld and that may be valid. You seem to check for valid senders and run into your own check trap.

Regards,
Christian