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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Yahoo Mail problems ? (queue issues in general)
On Wed, 05 May 2004 10:59:55 EDT, Mike Tancsa <[email protected]> said: > Anyone else seeing Yahoo mail queue up today ? Some of their servers > respond in about 10secs with the HELO banner, most others take more than > 2m. Because of the recent increase in SPAM, I was looking to reduce the > wait time for the initial HELO to 2m from 5m. However, the RFC calls for 5m > on the HELO and another 5m for the MAIL command. Do you have a handle on whether the delay is between the first SYN packet and finally completing the 3-packet handshake, or is it between that and when the 220 banner actually arrives? Or are both phases an issue? > Having a process block like that for up to 10m seems a bit excessive to > deliver one email (and its probably a bounce to boot!). What are others > doing? This problem seems to becoming more and more acute. What I do is the *first* attemt to deliver the mail has a highly-non-compliant 5 second timeout (which is just enough for an initial SYN, 2 retransmits, and a few hundred ms budget for RTT for a SYN+ACK) for the 3-packet handshake, and then subsequent retries in the background are given a longer 5-min timeout. (I gathered some stats for quite sime time before deploying that - out of several million connection attempts, I found less than a dozen that took over 5 seconds that did in fact complete in under 5 minutes). Once the 3-packet handshake succeeds, they then get a 5 minute timeout to get the 220 banner out. Probably not perfect, but it's close enough to keep the queues manageable... Also, YMMV, so gather your own stats.... Attachment:
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