Sendmail gives Deferred Connection timed out only to some domains

tdunk · 08-14-2008, 03:31 PM

Hi

I have a setup on FC7 64-bit using Scalix mail server and sendmail.

My problem is that I get the following errors in maillog when trying to send mails to some domains:

Code:

Aug 11 10:01:35 mail sendmail[7768]: m7B7tugB007762: to=<zzz@hotmail.com>, ctladdr=<root@mail.geniti.com> (0/0), delay=00:05:39, xdelay=00:05:39, mailer=esmtp, pri=120375, relay=mx2.hotmail.com. [65.54.244.40], dsn=4.0.0, stat=Deferred: Connection reset by mx2.hotmail.com

Aug 11 09:57:27 mail sendmail[7626]: m788Ee7q020724: to=<zzz@quickwood.com>, delay=2+23:42:46, xdelay=00:03:30, mailer=esmtp, pri=6694416, relay=mail.itfax.dk. [195.249.157.110], dsn=4.0.0, stat=Deferred: Connection timed out with mail.itfax.dk.

Sendmail keep trying to send and finally fails.
The strange thing is that I have no problem sending to some domains, but approx 5 domains (until now) have this problem including hotmail, but not e.g. gmail.

When inspecting the mails recieved at gmail from my mailserver it looks like this:

Code:

Received-SPF: pass (google.com: domain of zzz@geniti.com designates 87.61.115.66 as permitted sender) client-ip=87.61.115.66;
Date: Sun, 3 Aug 2008 16:04:27 +0200
From: ZZZ <zzz@geniti.com>
Reply-To: ZZZ <zzz@timemap.dk>
To: ZZZ <zzz@gmail.com>
Message-ID: <28302267.241217772267413.JavaMail.root@mail.geniti.com>
Subject: =Test
MIME-Version: 1.0
Content-Type: multipart/alternative;
   boundary="----=_Part_4_11794748.1217772267412"

------=_Part_4_11794748.1217772267412
Content-Type: text/plain;
   charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline
....

I have a reverse DNS for mail.geniti.com and I have tried raising some of the timeout options for sendmails, but still the same result.

I have no problem doing telnet on port 25 to the domains that fails so I think the problem is related to sendmail.

Perhaps 64-bit version of sendmail - is the 64-bit version buggy?

Any suggestions?

Thanks!

chort · 08-15-2008, 02:04 AM

What are the sites that you can't deliver mail to, and do you get the same error for each? It looks like in the case of Hotmail at least, they are intentionally rejecting your connection. It's probably an anti-spam measure on their side, although why they don't like your site is a mystery...

tdunk · 08-15-2008, 03:07 AM

Hi Chort

The domains that I have trouble with is:

- itfax.dk
- ingrammicro.de
- ingrammicro.se
- karbon.no
- hotmail.com

All the errors is the same, but the reson for hotmail reject might be spam issue as you suggest.

Before moving to FC7-64bit i used a FC6-32bit server and there sending to the above domain was ok.

The only thing beside upgrading to FC7-64bit is that the new server has a different internal ip address in the DMZ, but the public address is the same so I don't expect any problems related to rDNS.

I'll properly try to install sendmail 32-bit to see if that changes anything.

Regards

chort · 08-15-2008, 09:25 AM

Well if that's the only thing that changed at all, likely you just answered your own question.

tdunk · 08-19-2008, 06:53 AM

Hi

I finally fixed the problem.

After a firmware update on our firewall (Zywall) the problem have disappered and sendmail is now sending to all domains.

Hotmail is still slow to recieve, but the mails eventually go through.

Thanks for all advice.

Rgds