Inbound Email Delivery Failures (1000 characters per line)

I've been alerted by folks that some people are sending them email and they are not receiving it.  One would think this would be a simple matter to track down ***IF*** the Message Tracker was working properly (but, unfortunately, its not and we have been waiting quite some time for it to be fixed...)

Anyway, the Message Tracker shows the message coming in, but does not list any scanning state ("Message Details - None" - the usual Message Tracker Failure...).  So, I pull the SMTP logs and start scanning them.  I've noticed on several occasions now that the SMTP log has posted a "500 SMTP connection violates RFC5322 2.1.1 rule of 1000 characters per line.  Fix your mailer." entry associated with the corresponding message.  (To which I might reply "Fix your Effing Message Tracker", but I digress...)

So, I've seen this on several occasions now from several different sources.  These are simply folks trying to send us email and this doesn't appear to be a terribly isolated occurrence. I try to pass this info on to the senders but, as you might expect, they just consider US the source of their problems.  These folks can't do anything about "their mailer".  Many of them don't even know what "mail client" they are running.  At least some of them are running an obscure little email client named OUTLOOK.  I have one customer who simply refuses to send us email anymore and now always calls us instead (Thanks!)...

So, I'm trying to figure out if there is anyway to turn this "feature" off.  Their client doesn't care and my SMTP server (GroupWise) doesn't care.  The only one complaining here is SMG!  There is not a chance in hell I am going to convince the senders to change something on their side ("Fix your mailer") so if we want to get mail from them its now MY problem.  ...and once again, its one of those things that if you don't look for it, you might never know its happening.

I would expect, if we have some way to enable/disable/adjust this check, it should be in the SMTP Interface.  I have found a field labeled "Line Limit" and is set to 1000 but its under "External Delivery" and combined with Relay Server configuration so would appear not be be related to inbound email.  I'm hesitant to TRY any adjustments here as I don't want our site to become yet another one of these violators send email exceeding some RFC line limit... Tsk, Tsk!

Anyone know if its possible to turn this "feature" off or increase it or something so we can receive the associated messages from these scofflaws?

  • Thanks for the explanation, I understand more clearly now.  I was initially imagining SMG was doing more of a store-and-forward operation, but as you say it's a proxy.  The way the configuration works it feels more like store-and-forward, so I think the configuration influenced my imagination of the internal workings.  I'm coming from a email security/filtering system (Arista ETM, formerly Untangle) that is a config-less transparent proxy; all it does is "listen in" on any SMTP conversation flowing through it and stops the show if anything happens it doesn't like... it doesn't know anything about your domains, servers, users, etc.  It works reasonably well, but the complete lack of configuration options and the fact that it adds no new capabilities to the internet-facing SMTP service ultimately led me to SMG.

    Now that I understand I have no beef at all with the 1000 character per line limit; as long as the SENDING server is told 500 "fix your mailer" I'm good.  I've seen no evidence that any message blocked by this limit so far was one I wanted anyway.