Re: [Exim] Mail transaction failures

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Autor: Steven A. Reisman
Data:  
Dla: Odhiambo G. Washington
CC: Exim Users
Temat: Re: [Exim] Mail transaction failures
On Tue, Feb 05, 2002 at 01:55:16PM +0300, Odhiambo G. Washington wrote:

> Hello gurus,


> Here is another situation that has left me baffled. I am wondering if
> anyone of you have the same issues with this domain.
> One user I have is threatening to pull out alleging that he doesn't have
> similar problems using a neighbouring ISP.
> I don't have such issues with other hosts, including the one that handles
> this list ;-)
> I therefore assume that this problem is seen the world over, unless of
> course someone knows what I haven't told Exim to do for me. I have
> a 2Mbit uplink to the Internet, even...


This may or may not be your problem, but I've seen this happen with my DSL
customers running PPPoE. The encapulation increases packet size. When a
large packet hits an interface that won't fragment or totally blocks ICMP
packets (including Path MTU Discovery), timeouts like you're seeing occur.

To work around the problem we have our customers drop their MTUs from
1500 to 1450.


Some helpful Google queries: "pppoe mtu" and "icmp path discovery"


Steve


> Could this be a problem at my site??


>
>
> > This message was created automatically by mail delivery software (Exim).
> >
> > A message that you sent could not be delivered to one or more of its
> > recipients. This is a permanent error. The following address(es) failed:
> >
> >   sur.mjmiel@???
> >     Operation timed out:
> >     SMTP timeout while connected to relay.lon.equant.net [57.250.220.29]
> after end of data (4297 bytes written):
> >     retry timeout exceeded
> >   ho.mflavictoire@???
> >     Operation timed out:
> >     SMTP timeout while connected to relay.lon.equant.net [57.250.220.29]
> after end of data (4297 bytes written):
> >     retry timeout exceeded
> >   ho.vscaglia@???
> >     Operation timed out:
> >     SMTP timeout while connected to relay.lon.equant.net [57.250.220.29]
> after end of data (4297 bytes written):
> >     retry timeout exceeded

> >
> > ------ This is a copy of the message, including all the headers. ------
>
>
> TIA
>
>
> -Wash
>
> S y s t e m s A d m i n.
>
> --
> Odhiambo Washington  <wash@???>    "The box said 'Requires
> Wananchi Online Ltd.  www.wananchi.com      Windows 95, NT, or better,'
> Tel: 254 2 313985-9   Fax: 254 2 313922     so I installed FreeBSD."
> GSM: 254 72 743 223   GSM: 254 733 744 121  This sig is McQ!  :-)

>
> ++
> Basic, n.:
>     A programming language.  Related to certain social diseases in
> that those who have it will not admit it in polite company.

>
> --
>
> ## List details at http://www.exim.org/mailman/listinfo/exim-users Exim details at http://www.exim.org/ ##
>
>


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Steven A. Reisman          <sar@???>           P.O. Box 409
PressEnter LLP                                        421 N 2nd Street
715-426-2100 or 651-436-5254                    River Falls, WI  54022
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