The MaxMTAOps variable have nothing to do with 'dns' name resolution
mechanism so dns name resolution problems will 'normaly' not be resolved
increasing this parameter (except bug in xmail, but I don't think, dns code
is very isolated from mails process in xmail code)..

If you have a 'Mail loop detected', even you can have two sort of reasons :
- Real loop : some server in the route resend the mail to one of the
previously used smtp servers (or itself) in the 'route' to the last, and
your server is one that receive again and again the message (it detect loops
regarding smtp headers counting the Received: lines).
Nothing to do here on your xmail server to correct this problem, the mail is
in a loop, increasing MaxMTAOps will not correct the 'loop'
Very likely some chain of forwarding accounts that send to others forwarding
accounts, that ... and another forwarding account 'forwarding' back in the
chain, in this case find the 'back forwarder' and correct the forward will
be the only solution
To know if this is the problem, try capture the mail reaching your server
again in again (see logs, ... use a filter) and verify the Received: headers
chain to see a loop

- In normal situation on the Internet it's rare to reach the default 16
'MaxMTAOps', even with big ISP having many servers (front ends, avscan, spam
scan, , backends, forwarders, final clients servers, ... if each task in a
different server). But if you suspect this is the problem ^(and not a real
loop) try increasing by steps (say by 4 step, 20, 24, ...) until the 'loop'
detection stops (if you reach more than 32, I think it’s a Real Loop you


-----Message d'origine-----
De : xmail-boun...@xmailserver.org [mailto:xmail-boun...@xmailserver.org] De
la part de David Lord
Envoyé : mardi 16 octobre 2012 18:15
À : U.Mutlu
Cc : xmail@xmailserver.org
Objet : Re: [xmail] Dbg&Fix: Mail loop detected

On 12 Oct 2012 at 16:54, U.Mutlu wrote:

> Just wanted to share a "debug session" to trace down a "Mail loop
detected" situation:
> A bounce mail with reason "Mail loop detected" is generated under this
>   if it takes too many steps (operations) to get the first MX record
>   (or the final A record when MX is missing after trying all)
>   of the recipient domain than what is defined in server.tab under
>     "MaxMTAOps"     "16"

I had problems with some mailing lists and over a period gradually increased
MaxMTAOps to 28. 

Oldest server.tab in archive on this server is Jul 7, 2009 and that has
'"MaxMTAOps"  "28"' and other changes go back to 2005.


> For example:
> I had a mail to an address xx...@embarqnow.net and got that error 
> because that domain has many nameservers and a depth of 3 levels to 
> finally get the MX record, but the number of steps to get to the MX 
> exceeds the above defined 16 ...

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