"Errormail" attaches whole bad message - and creates deadlock

[aal@cpr.spb.ru (Alexey Lobanov)]

Hello.

I can see that the current error notification scheme can create 
rare but heavy deadlocks in mailserver.

I have several hosts with Zmailer, and all them have same SMTP 
message size limit (2 000 000 bytes.) Surely, I (postmaster) 
read mail at one of them, other ones forward mail to me.

Now, a message of 1 999 950 bytes arrives to valid user at one 
server and attemts to travel to another (i.e., better MX). But 
now it is 2 000 030 bytes because of "Received:" string, and 
next hop bounces it!

OK, this first situation is inpleasant but not dangerous. Nobody 
warranties huge message delivery.

Next step is more bad. Normally Zmailer creates error 
notifications (forms/delivery) messages attaching WHOLE bad-
behaving message as message/rfc822 attchment. This bundle is 
definitely bigger than SMTP limit. And if <postmaster> mail is 
forwarded to another host, it is bounced too... creating new 
huge error messsage... bounced again... new error... LA=1.5 
until manual message kill.

The quick solution is just to require Postmaser to be local. I 
am not sure that it is feasible limitation.

Some MTA (i.e., Postfix) show smarter behavoir: attached bounced 
message is always cut to safe (typically, 50 kb) size. That's 
enough both for sender and postmaster to identify message and 
error reasons. Moreover, a good practice is to send message 
headers ONLY to postmaster, protecting sender privacy.

So, the question: how can I make Zmailer to attach message 
headers ONLY to error notification?

Alexey


====
Alexey Lobanov
al258-ripe
CPR, St.Petersburg
Head, IT Department
Phone +7-812-3468247
Fax +7-501-3468248, +7-812-3271408