If you ever wanted to chase down the MTU issue from a Win32 perspective you could try this free tool: http://www.elifulkerson.com/projects/mturoute.php

Pleas share the working and not-so-well-working IPs so we can compare to our own logs.

Frank

-----Original Message-----
From: Ed [mailtoHIDDEN@ent.net] 
Sent: Monday, September 08, 2014 10:12 PM
To: surgemailHIDDEN@etwinsite.com
Subject: Re: [SurgeMail List]HIDDEN@m and @icloud.com

Hi,

PMTU I don't think so.

We did find that me.com and aliases advertise a whole big pile of MX's. 
  After some testing we found that some MX's work great every time, some 
fail most times -- not all [how odd].  Hmmm !  So luck of the draw ? 
Also we found that each of those MX's actually front for multiple 
different servers ie load balancing and they overlap too.  Oh so cool ;-)

Knowing the IP of a good one we just added a little configuration for 
those 2 domains to route to that IP and life is one again good, at least 
for now.

We will have to get into this a bit deeper.  I was actually entertaining 
the idea we've got an MTU mismatch someplace upstream, seen that action 
before but I'm not really sure of that because those 2 domains are the 
only ones giving us a problem.  And it's obviously not an RBL issue either.

Thanks!
--Ed

On 09/08/2014 10:59 PM, Frank Bulk wrote:
> We've not seen any issues.  Anything possibly PTMU related?
>
> Frank
>
> -----Original Message-----
> From: Ed [mailtoHIDDEN@ent.net]
> Sent: Monday, September 08, 2014 11:14 AM
> To: surgemailHIDDEN@etwinsite.com
> Subject: [SurgeMail List]HIDDEN@m and @icloud.com
>
> Has anybody out there had an issue sending email to me.com and
> icloud.com which are really the same place.
>
> This all seems to have started a couple months ago.  It's the only place
> we're having an issue with so not a network or server issue because all
> of our servers are experiencing the same issue and have zero delivery
> issues any place else.
>
> We're getting
>    after data sent: 421 4.4.2 Timeout while waiting for command.
> and
>    Write failed 100 times or 550>540 seconds 550, wrote 37305/1485 left
> (37305)
>
> which is quite bizarre.
>
> If so did you fix it and how.
>
> Thanks!
> -- Ed
> -----------------------------------------------------------
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>
>

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