[Mailman-Users] Analysis of reasons for bounce responses

[Jon Carnes]

On Thu, 2003-07-31 at 06:08, Richard Barrett wrote:
> This is not my problem but one soemone approached me about off list.  
> I'll summarise their situation and I would appreciate any thoughts,  
> comments, sanity checking on my analysis.
> 
> Situation:
> 
> 1. List admin's domain is hosted by a server run by a hosting company.
> 
> 2. The server is (probably) running Linux
> 
> 3. Mailman 2.1.2 is provided on the server with, I believe, CPanel
> 
> 4. The server's MTA appears to be Exim 4.20 handling both incoming and  
> outgoing messages to/from Mailman
> 
> 5. Mailman list's basically work OK much of the time
> 
> 6. Periodically messages out from Mailman are being bounced en masse  
> leading to the subscriber accounts being disabled
> 
> 7. The bounce response attached to the bounce action notice produced by  
> Mailman when subscribers are disabled in these circumstances is from  
> the server local MTA. The MTA lists what appears to be all the  
> addresses to which the outgoing message was sent with a note against  
> each saying "unrouteable mail domain maildomain.tld". The bounce  
> response asserts that this is a permanent failure. The messages are  
> each being sent to a number of different mail domains not just a single  
> one
> 
> 8. The list admin with the problem has no access to either the Mailman  
> or MTA logs
> 
> 9. The server administrator is supposedly claiming that these bounces  
> are a result of "a bug in Mailman for which no patch is available"
> 
> My analysis is:
> 
> 1. The problem is not obviously due to any bug in Mailman
> 
> 2. The problem is more likely due to an IP routing problem which  
> periodically afflicts the server and its ability to reach the MTAs for  
> the mail domains addressed by the outgoing messages
> 
> 3. The MTA is accepting the outgoing messages from Mailman and then  
> finding it has problems of its own in delivering mail which are  
> unrelated to Mailman as the origin of the messages
> 
> But I have to concede I know nothing about Exim 4.20. I know even less  
> about CPanel.
> 
> Any thoughts or anatomically feasible suggestions welcome.
> 
I have seen this behavior a few times and in each case it was resource
problem on the server.  They need to check on the memory of the box and
how much is being used during the bounces.  I'm afraid it is only
something that the sysadmin can really do.

I have also seen this problem when the /var directory was made too
small. Could this be a problem with the users services being chrooted
and them running out of quota space while processing large messages?

Good Luck - Jon Carnes