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Brad Fitzpatrick

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Yahoo's mail servers [Aug. 17th, 2006|02:08 pm]
Brad Fitzpatrick
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I now have scientific evidence that Yahoo runs the worst mail server farm on the Internet.

Publication of results to follow.

Update: Randy thinks this is too harsh and got me in contact with the Yahoo folks. What I said to Yahoo:
We're actually not quite sure if Yahoo's mail servers "suck" or if they're just really aggresive in their anti-spam efforts.

The success rate of a TCP connect to any of the IPs in the first 3 mx records happening within any sane amount of time is relatively low, compared to other mail servers on the Internet. Sometimes an IP will take a connection in milliseconds, followed by 15 - 120+ seconds the next time (on the same IP), followed by milliseconds again. So it doesn't /seem/ like anti-spam or rate limiting, but instead like poor load balancing.

Or maybe this is intentional and we need to get onto a bulk sender whitelist? I have no clue how your incoming mail servers are setup, though.
From my perspective, Yahoo is the only big email provider whose email servers don't answer somewhat immediately, and my logs are filled with errors that we couldn't establish a connection to *any* of their MX servers in a reasonable amount of time, so mail to Yahoo users had to be delayed until a future attempt.

If Yahoo wants to greylist me or even tell me "4xx too busy try later" immediately upon connect (which they do, sometimes), I'm fine with that. But not even taking a connection for 12+ seconds is just ridiculous. I send email to gmail and it's taken in milliseconds and is server-pushed to the gmail client in the browser within a second after that. That's just impressive. Not so impressed with Yahoo's end-to-end.
LinkReply

Comments:
[User Picture]From: krellis
2006-08-17 09:03 pm (UTC)
Ooh, yes, I'd love to see the results. I can certainly correlate your findings from my own experiences from attempting to forward mail to customers with Yahoo mail addresses. They return 4xx "we're too busy" responses so often it's kind of sickening.
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[User Picture]From: brad
2006-08-17 09:04 pm (UTC)
When they have the time to SYN+ACK.
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[User Picture]From: krellis
2006-08-17 09:05 pm (UTC)
True enough. And yet, my Yahoo account still manages to get boatloads of spam. Hmmm........ :)
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(Deleted comment)
[User Picture]From: brad
2006-08-17 09:26 pm (UTC)
I'm quite sure they do anti-spam, but this doesn't look like it.
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[User Picture]From: brad
2006-08-17 09:40 pm (UTC)
What about their servers taking anywhere from 0.10 second to over 120 seconds to connect?

But with no apparent history per IP or subnet: they're not remembering I'm good or bad it seems. It suggests their load balancing is pretty weak.

I don't mind the 4xx on connect.
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[User Picture]From: flashfire
2006-08-17 09:06 pm (UTC)
In my job we deal with a TON of Yahoo e-mail users and I can say without a doubt that the number of e-mails that bounce for that very reason is insanely high.
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[User Picture]From: dormando
2006-08-17 09:04 pm (UTC)
Really now!

I love how we have to use a hack to force postfix to flood yahoo's servers just to get the mail across. Even when we're on their damn whitelist (followed closely by hotmail's similar behavior).

This will be interesting :)
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[User Picture]From: dormando
2006-08-17 09:05 pm (UTC)
By that, I mean the ratio of "250 ok" vs "connection timed out? what the fuck?" is sickening.
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[User Picture]From: scathedobsidian
2006-08-17 09:45 pm (UTC)
Hotmail has always seemed about fifty times ahead of Yahoo in this category to me, actually.
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From: (Anonymous)
2006-08-17 10:08 pm (UTC)

have you reached this conclusion from our house?

Have you reached this conclusion trying to send mail out from our house using outgoing.verizon.yahoo.com? Because I have seen a high rate of failure trying to send outgoing mail since switching from Comcast (which timed out all the time in the middle of Cole's games) to Verizon FIOS with Yahoo.
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[User Picture]From: brad
2006-08-17 10:13 pm (UTC)

Re: have you reached this conclusion from our house?

No.

From a real connection.
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[User Picture]From: muerte
2006-08-18 03:59 am (UTC)
I knew I'd heard about something like this before. I did some digging and found an article on the very subject. This is a semi-recent article though, I'm sure I remember something older along the same lines.
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[User Picture]From: brad
2006-08-18 04:04 am (UTC)
Heh. Love the final rebuttal from Yahoo, that they handle more mail than the post office and Fedex combined.
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[User Picture]From: muerte
2006-08-18 04:16 am (UTC)
I can't find the other article, but someone did a test on all their servers. Graphed the availability of their servers over the course of two weeks or something. At any given time no more than like 30% of their servers even responded on port 25. Crazy.
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[User Picture]From: davidjacobs
2006-08-18 12:00 pm (UTC)
I think this is the article you're referring to. Yahoo sure does handle a lot of mail, but that's no defense. Their mails servers are horrificly slow.
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[User Picture]From: brad
2006-08-18 04:17 pm (UTC)
Nice, thanks.
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From: retrogradeheart
2006-08-18 04:03 am (UTC)
It doesn't seem right to compare Yahoo's mail service (which services 300 million accounts) with Google's (which doesn't have nearly that many). Not that I'm defending their behavior, but as a matter of scale it doesn't seem like the right comparison to make.

(full disclosure: I am a yahoo employee but I don't work on mail)
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[User Picture]From: brad
2006-08-18 04:05 am (UTC)
Mail scales out horizontally so, so easily. Buy more servers. Or improve the load balancing algorithms.
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[User Picture]From: graceadieu
2006-08-18 04:39 am (UTC)

Actually...

that designation "worst on the planet" is the sole property of Roadrunner. Roadrunner automatically deletes every single email we receive that has an attachment of any kind, including photographs of my cousin's children! It even deletes an attachment I sent from my Yahoo email to my Roadrunner email that was nothing more than a recipe for barley soup! They drive me absolutely postal, no pun intended.
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[User Picture]From: xlerb
2006-08-18 10:01 am (UTC)
mmmmmmm, fallback_relay.

Well, only if they actually time out the connect. If they 4xx, not so much.
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[User Picture]From: brentdax
2006-08-18 11:36 am (UTC)
Well, nobody else seems to have Google's attitude of "do it right or don't do it at all", which is a shame.
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[User Picture]From: fanf
2006-08-21 10:20 pm (UTC)
I've noticed that Outblaze's servers are routinely slow, but I think that's deliberate tarpitting or greeting delays.
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From: (Anonymous)
2006-11-02 03:46 pm (UTC)

Pompiliy

nice project with good design and pictures...best wishes...;-))
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