[BlueOnyx:09140] Re: Smtp errors

[Jeff Folk]

On Nov 28, 2011, at 2:33 PM, Hugo Sesma wrote:
> 
> Hi,
> 
> One of our coustumers can't recive mail from a specific domain. Searching in the mail log I've found this log entries.
> 
> Nov 25 09:05:40 ns1 sendmail[32559]: pAPF06Sd032559: SYSERR(root): collect: I/O error on connection from smtp.mm.xxxx.com, from=<user at mm.xxxx.com
> >
> Nov 25 09:05:40 ns1 sendmail[32559]: pAPF06Sd032559: from=<
> user at mm.xxxx.com>, size=0, class=0, nrcpts=1, proto=ESMTP, daemon=MTA, relay=smtp.mm.xxxx.com
>  [187.174.140.198]
> Nov 25 09:21:24 ns1 sendmail[1241]: pAPFE1Uc001241: collect: premature EOM: Connection reset by 
> smtp.mm.xxxx.com
> After this I've made some research in the web and find there was 2 options configuration error in sendmail.mc specific for version 8.7 or blacklist servers not responding.
> 
> I don't feel conformtable messing with sendmail configuration files. 
> 
> So any sugestions will be apperciated.
> 
> May be a clue to all this could be a very slow delivery time and trouble with large atachments >2 Mb.
> 
> thanks in advance.
> 
> H.

Are you (or the sending server) blocking ICMP? MTU discovery uses ICMP to negotiate MTU.

Regards;
Jeff