Comments on: Mobile users can't send mail through Postfix on my XServe.

Question: Mobile users can't send mail through Postfix on my XServe.

odinsdream — Tue, 02 Oct 2007 15:33:48 -0800

XServe Postfix: How can I disable hostname verification so that mobile users can send mail successfully through my server?

One of our mail users cannot send messages through our server from her BlackJack phone. Checking the SMTP logs, I see lots of this:

Oct 2 18:15:11 rammserve postfix/smtpd[12253]: warning: 32.161.215.131: hostname mobile-032-161-215-131.mycingular.net verification failed: Host not found

Googling indicates that this is because the hostname has no PTR record. Nothing I can do about that, so I'm looking to disable this check. It's apparently due to the reject_unknown_client_hostname configuration directive, and/or something in smtpd_helo_restrictions.

However, I can't find where any of this stuff is enabled on the server. It's a default configuration XServe. I've looked over the output from postconf -d, but can't find anything that's causing this warning. Where else should I look? Is this even the problem? If not, what else?

By: marionnette en chaussette

marionnette en chaussette — Tue, 02 Oct 2007 15:58:44 -0800

'postconf -d' outputs the default configuration for postfix, not what's actually set on your server. Run postconf by itself.

By: odinsdream

odinsdream — Tue, 02 Oct 2007 16:22:15 -0800

Ah. I've updated the above link to show the output of postconf. Thanks.

By: Steven C. Den Beste

Steven C. Den Beste — Tue, 02 Oct 2007 18:06:53 -0800

I don't have an answer for you, but I do have a warning: make sure you don't turn your server into an open mail relay, to be found by and abused by spammers.

By: dreadpiratesully

dreadpiratesully — Tue, 02 Oct 2007 18:19:00 -0800

It's been a while, but if I recall correctly the warning you're seeing will show up whether the mail is rejected or not. Is there another entry in the log about the rejection? Or a bounce sent to the user?

By: Jerub

Jerub — Tue, 02 Oct 2007 18:52:42 -0800

Don't accept mail on port 25. Use port 587, aka 'submission'. It's for submitting mail to mail servers by authenticated external clients.

Add to master.cf:

587 inet n - n - 12   smtpd -o smtpd_enforce_tls=yes -o smtpd_sasl_auth_enable=yes

in main.cf under "smtpd_sender_restrictions" you want to have "permit_sasl_authenticated" listed before "reject_unknown_client_hostname". This will mean that any mail sent by clients using authentication will be accepted.

You'll need to get sasl auth working, docs are here if you don't already have that.

By: odinsdream

odinsdream — Tue, 02 Oct 2007 20:38:51 -0800

dreadpiratesully, nope, no bounce was sent. The user reports that an error message is presented on her phone soon after she clicks send. This is the only message that shows up in the logs, so I was hoping I was on to something.