On Fri, 8 May 2009, Mark wrote:
From: Charles Gregory [mailto:cgreg...@hwcn.org]
Do yahoo and python.org enforce a shorter time-out?
Highly doubtful. RFC 2821, Section 4.5.3.2 ("Timeouts") gives you a 2
minutes window while awaiting the "354 Start Input" reply to a DATA
command.
...are you sure that's the timeout he's referring to? How does SA come
into play **before** the sending MTA sends the message body?
I suspect the sender is timing out waiting for the "250 OK" after sending
the message, hence my (humorous) "100 Please hold..." suggestion. (Jeeze,
SM, lighten up!)
Per RFC2821, the timeout for the "250 OK" is ten minutes, but again, those
are SHOULDs.
And I can see a busy list server reducing those timeouts a bit - they are
sending a _lot_ of mail.
The mail was getting delivered to my local recipient, but the sending
system was resending a few minutes later (and would do so three or
four times).
It's quite possible for a connecting mail server to retry after it
received, say, one of the many 4.x.x codes. However, what's definitely
broken in your setup is that, in such a scenario, apparently your LDA
already delivers (part of an) aborted mail. That seems too strange for
words; so, likely, you're not sending out proper reply codes to
connecting mail servers.
So, the solution is simple: fix your mail server; or have someone do
it for you.
More likely the client is disconnecting after the timeout and _assuming_
a 4xx state, and requeueing the message. If there's any problem with
Charles' server it's that it continues delivery after the sending client
has dropped the connection. I wouldn't really see that as a problem,
though, as I'd rather get multiple deliveries in that case than have
both sides make assumptions the other direction and _lose_ the message.
Charles, here's something you could try: using telnet, connect to your
MTA and pretend you're the yahoo listserv. Feed in one of the
problematic messages, and time how long it takes from sending the final
period to receiving the 250 OK. That will give you something to compare
to how long it takes to scan the message outside of your MTA
envrionment.
--
John Hardin KA7OHZ http://www.impsec.org/~jhardin/
jhar...@impsec.org FALaholic #11174 pgpk -a jhar...@impsec.org
key: 0xB8732E79 -- 2D8C 34F4 6411 F507 136C AF76 D822 E6E6 B873 2E79
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