Re: attachment / yahoo issue

Steve Baker wrote:

On 13 Jun 2006 07:18:04 -0700, "Grip" <grip@xxxxxxxxxxxxx> wrote:


I sent my hosting company the header from my e-mail. I've included the
relevant "recevied lines" but xxx out any info that might compromise my
security. Below that is the e-mail response I received from my tech
support. Are they just passing the buck?


It looks like they "spiced it up" a bit, but the ultimate explanation
that it took several tries to deliver to Yahoo sounds very reasonable.
Especially since they seem to have checked their logs and counted the
number of tries it took. The stuff about "different networks" and
"different paths" is BS. The stuff about Yahoo's spam filters could be
plausible. They don't say exactly what "timed out". It could be that
their server "timed out" waiting for a response from Yahoo after they had
sent the body of the email... and the reason for that could be that Yahoo
took a while deciding whether or not it wanted to accept that email
(because of the size of the email and consequent processing time). Or
maybe Yahoo does Greylisting, which requires retries, but 11 hours sounds
like a long time for that. But, that could account for the different
performance for different senders; Sender A gets Greylisted, Sender B
doesn't. Along those lines, it could also be, like they said, that some
senders have their email more closely scrutinized than others.
Nothing I came up with really seems to nail it, I just felt like
tossing out some ideas. A relatively short "time out" on their server
waiting for a response seems most likely. Eventually their server would
retry when Yahoo wasn't so busy, so the processing would go faster, and
the "time out" wouldn't happen. Do you always send those attachments at
roughly the same time of day? 7 PM on the west coast is probably a very
busy time of day.

Just purely guessing,
Steve Baker


Thanks
G


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I've spoken with my NOC guys who deal with yahoo and here is there
response with respect to their being a 12 hour delay for the delivery::

Delays can occur because of the destination mail servers timing out,
either because of an internet connection, or because it is planned, and
in this instance that is the case. Yahoo has always been quite
aggressive with filters and therefore mail going to them has always
been anything other than rock solid. You cant blame them since it is a
free email service.

There will always be delays going to yahoo, until they change their
filtering.

As far as emails through other accounts getting through more quickly,
it's likely
that Yahoos filtering targets non-isp emails more agressively than ISP
emails. Your other account Cybermesa is a known ISP, and their filters
may treat
differently a mail sent from a website mail server (mail servers are
where spam is generated from. ISP's don't allow the sending of spam -
they institute max recipients, max sizes and other methods that limit
what and how a user can send... Our mail servers do not restrict what
and how much can be sent, Yahoo knows this so they look at mail from
such sources with greater scrutiny)

As to the actual specifics of how Yahoo filters and targets, you would
need to contact yahoo directly. We can only make educated and fairly
informed guesses.

Additionally the path from the mail server to Yahoo is different from
the path takes, so it's very very difficult to compare. Different
networks, different
paths, different things going on from one moment to the next.

In short, the delivery on the email headers you sent timed out as did
the the following 2 attempts (attempts are made every four hours up to

4 days). The fourth attempt was successful and the mail was delivered.


AK wrote:

Grip wrote:


Whenever I send an e-mail with an attachment from my email account to a
Yahoo address, it takes 1-2 days to show up in the recepient's inbox.
Only Yahoo, only with an attachment, and only when sending through my
domain name. It doesn't get spam blocked it just takes a really long
time to arrive.

My hosting company says they have no idea why or how that could be
happening.

Any ideas?

G


Hmm.

Without the header information it is impossible to answer your question.
The three entities that can be at fault are your the firm through whom
you send the message, the receiving (yahoo) or you (if you only queued
the message, but did not actually send it)


One way to determine the cause for the delay is to look at the full
message headers and see between which hopes (mail server to mail server)
the message was delayed. once you see where the mailing was delayed you
could proceed with dealing with the entity.

AK





I would agee with Steve. Usually if the sending server reaches the time wait threshold and disconnects, the recipient will likely get duplicates since the message was actually delivered to the receiving server, but the sending server had not received the status message for the delivery. The requeing or the redelivery attempt depends on each sending server. Some have automatic scheduler and some, primarily batch type queues, will attempt redelivery on a set schedule.

With the filtering, one should allow for up to 10 minutes prior to disconnecting. The likely config on the mail servers prior to spam (dark ages) was to have the timeout at 2 minutes.

Since you brought this matter to the attention of your NOC, hopefully they increased the timeout for the SMTP session.

If you want to experiment, you could send emails with attachments of various sizes. Using that you can narrow down at which message size you might encounter delays due to processing/originating server's timeout.

AK

.