Yahoo! Mail Issue

Matthew Petach mpetach at netflight.com
Tue Apr 12 02:33:05 CDT 2011


On Tue, Apr 12, 2011 at 12:12 AM, Nathanael C. Cariaga
<nccariaga at 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 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
>>>>
>>>>
>>>
>>
>>
>
> --
> 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 at stluke.com.ph
>
>




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