Handle misconfigured MX records

Post your MailEnable suggestions here.
Monty_Python
Posts: 45
Joined: Sat Sep 13, 2008 7:51 pm

Post by Monty_Python »

Please excuse the windroid that needs help with a mail loop, he has a steep learning curve to follow.

MailEnable
Site Admin
Posts: 4441
Joined: Tue Jun 25, 2002 3:03 am
Location: Melbourne, Victoria Australia

Post by MailEnable »

No need as yet, I will look into it and see whats going on. I may have misread te setting - or the setting or something. If the forum gets cluttered, I will just purge.
Regards, Andrew

MailEnable
Site Admin
Posts: 4441
Joined: Tue Jun 25, 2002 3:03 am
Location: Melbourne, Victoria Australia

Post by MailEnable »

I have not fully tested yet (and will post when i have), but it seems you will need another key:
Loop Detection Enabled
DWORD set it to 1 - in the same branch.

FYI: It seems from further research that ms exchange uses a loop detection value of 30 and postfix uses 50.
Regards, Andrew

MailEnable
Site Admin
Posts: 4441
Joined: Tue Jun 25, 2002 3:03 am
Location: Melbourne, Victoria Australia

Post by MailEnable »

Brett, I just tested by sending a message to the sna.com domain.

Even with the default setting (ie: without any of the reg changes i mentioned) it will detect the loop - or at least it does so on mine.

This is what would appear in the mta debug log when it exceeds the 20 threshold.

Message (xxx) from (xxx) could not be delivered as an infinite message loop was detected. (ERROR MTA-1010)

My test was to simply use an imap/smtp client from outlook. The server has relay granted for 127.0.0.1 to allow the loop to occur. I sent a message to the user test@sna.com.

The message then cycles and is detected and placed in the badmail folder.

Maybe you could try the same test and see what happens.
Regards, Andrew

Monty_Python
Posts: 45
Joined: Sat Sep 13, 2008 7:51 pm

Post by Monty_Python »

I don't see Postfix falling to it's knees when mail loops back to itself. Mind you, any MTA in the hands of an idiot has the potential to s**t the bed. Perhaps entering the correct details and recipient when sending an email, or finding a negro in one of the townships with some savvy, and the problem may not have appeared in the first place.

Brett Rowbotham
Posts: 560
Joined: Mon Nov 03, 2003 7:48 am
Location: Cape Town

Post by Brett Rowbotham »

I ran a test after setting both items in the registry and by the time I stopped the MTA the message had 55 received lines.

Do the Received headers have to be consecutive from the start of the message ? We run SpamAssassin on incoming email so there is a gap in Received headers at the start of the file as follows:

Code: Select all

Received: from MYDOMAIN ([XXX.XXX.XXX.XXX]) by MYDOMAIN with MailEnable ESMTP; Tue, 1 Sep 2009 14:34:04 +0200
X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on WEBSERVER
X-Spam-Level: 
X-Spam-Status: No, score=-3.5 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00
	autolearn=ham version=3.2.5
Received: from MYDOMAIN ([XXX.XXX.XXX.XXX]) by MYDOMAIN with MailEnable ESMTP; Tue, 1 Sep 2009 14:33:55 +0200
Received: from MYDOMAIN ([XXX.XXX.XXX.XXX]) by MYDOMAIN with MailEnable ESMTP; Tue, 1 Sep 2009 14:33:47 +0200
Received: from MYDOMAIN ([XXX.XXX.XXX.XXX]) by MYDOMAIN with MailEnable ESMTP; Tue, 1 Sep 2009 14:33:30 +0200
....

MailEnable
Site Admin
Posts: 4441
Joined: Tue Jun 25, 2002 3:03 am
Location: Melbourne, Victoria Australia

Post by MailEnable »

Yes, that is why - the loop detection assumes they are consecutive.

I have patched the smtp executable to accommodate the more desirable fix. http://www.mailenable.com/beta/upload/mesmtpc.exe. You could try replacing the executable as an interim workaround.
Regards, Andrew

Post Reply