Re: Yahoo! Mail Issue

[Matthew Petach <mpetach () netflight com>]

On Tue, Apr 12, 2011 at 12:12 AM, Nathanael C. Cariaga
<nccariaga () stluke com ph> wrote:
> Strangely though I noticed that the email accounts that seems to be affected
> by our concern seems to be related to the Yahoo SG servers.....

Oh.  You don't seem to want to accept connections from the singapore
servers at all:

-bash-3.2$ telnet qc.stluke.com.ph 25
Trying 219.90.94.56...
Connected to qc.stluke.com.ph.
Escape character is '^]'.
550 Blacklisted: Blocked - see http://www.spamcop.net/bl.shtml?115.178.12.223
Connection closed by foreign host.
-bash-3.2$

So, they really can't send mail to your users--but it's your machine
rejecting the connection.  :/

Matt

> On 4/12/2011 3:04 PM, Christopher Balmain wrote:
> > 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 () 2mbit com>   wrote:
> > > > > On 4/11/11 10:47 PM, Matthew Petach wrote:
> > > > > > mpetach@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@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
>
> --
> Nathanael C. Cariaga
> Network & Security Administrator
> St Luke's Medical Center
>
> Tel (QC) :  +63 2 723 0101 ext 5520 / 4206
> Tel (GC) :  +63 2 789 7700 ext 6035 / 6036
> Tel      :  +63 2 356 5686
> Mobile   :  +63 922 8735686
> EMail    :  nccariaga () stluke com ph