Yahoo! Mail Issue

Christopher Balmain chris at team.dcsi.net.au
Tue Apr 12 02:04:56 CDT 2011


We had a lot of issues delivering mail to yahoo.com.sg about a year ago
(just the .sg domain, plain .com was fine). Could establish connection
but it'd die halfway through transferring mail. A static route to drop
the MTU (for their subnet only) to 1000 fixed the problem right up.

Not sure if pmtud was/is broken or what.

- Chris

On Tue, 2011-04-12 at 15:29 +1000, Nathanael C. Cariaga wrote:
> Thanks anyway.  I just find this issue intriguing since not all Yahoo 
> mail accounts are affected.  In addition, incoming mails from other 
> domain doesn't seem to be affected.  That is why I want to check if it 
> is a network issue :)
> 
> -nathan
> 
> On 4/12/2011 1:17 PM, Matthew Petach wrote:
> > On Mon, Apr 11, 2011 at 9:54 PM, Brielle Bruns<bruns at 2mbit.com>  wrote:
> >> On 4/11/11 10:47 PM, Matthew Petach wrote:
> >>> mpetach at opstools1:~>    telnet 219.90.94.56 25
> >>> Trying 219.90.94.56...
> >>> Connected to static-host-219-90-94-56.tri.ph.
> >>> Escape character is '^]'.
> >>> ehlo yahoo.com
> >>> 554 SMTP synchronization error
> >>> Connection closed by foreign host.
> >>> mpetach at opstools1:~>
> >>>
> >>>
> >>> I imagine when port 25 stops giving 5xx
> >>> failure message back, mail reception
> >>> might improve.   ^_^;
> >>
> >>
> >> Works fine for me, your getting an error because your trying to send a
> >> command before receiving the first 220, aka RFC violation.  As long as you
> >> connect, wait a moment without trying to send a command, your fine.
> >
> > Doh!
> >
> > See, that's what happens when you ask networking people
> > to try to troubleshoot mail issues.  ^_^;;
> >
> > Sorry about that.  :(
> >
> > Matt
> >
> >
> 





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