Are your users having problems sending to Yahoo?

[nickn]

Just trying to poll some data to narrow this down...

grep -r yahoo /var/log/exim_mainlog | grep retry
grep -r yahoo.com /var/spool/exim/input | grep From: | wc -l

The way cpanel has exim configured out of the box, it has a very generic,
probably overlooked retry configuration, basically it will retry every 15
minutes for 2 hours. The problem here is graylisting is getting popular.
You end up with something like this :

2006-10-23 08:47:11 1Gc08F-0002d2-0c == g@yahoo.com R=lookuphost
T=remote_smtp defer (-53): retry time not reached for any host
2006-10-23 09:07:12 1Gc08F-0002d2-0c == g@yahoo.com R=lookuphost
T=remote_smtp defer (-53): retry time not reached for any host
2006-10-23 10:23:05 1Gc08F-0002d2-0c == g@yahoo.com R=lookuphost
T=remote_smtp defer (-53): retry time not reached for any host


The issue here is, with graylisting, you should retry at least once,
initially, almost immediately. For whatever reason, exim isn't allowing
itself to retry properly.

It's something to look at, since yahoo implemented graylisting 2 days ago,
we've had hundreds of customers complaining, because their email are being
rejected, and for whatever reason, since the retry times aren't optimized,
it's taking at least 15 minutes, often a few hours, to retry.

Any thought on this? The other issue is the queue runner by default only runs every hour.

You can set a specific retry interval for the 451 error, which is what should be done (rcpt_451) something such as :

* rcpt_451 F,1m,3s; F,1h,5m; F,3h,30m;


lemme know.

[nickn]

Not sure why this is happening, but it's a huge problem on Yahoo's end... all of their mailservers seem to be greylisting (451 Message temporarily deferred - 4.16.50451 Message temporarily deferred - 4.16.50). I wonder if it'll actually cut down on spam, or just cause legit server admins headaches...

Matt

It's not a problem on Yahoo's side - it's greylisting. http://en.wikipedia.org/wiki/Greylisting

[mainarea]

Not sure why this is happening, but it's a huge problem on Yahoo's end... all of their mailservers seem to be greylisting (451 Message temporarily deferred - 4.16.50451 Message temporarily deferred - 4.16.50). I wonder if it'll actually cut down on spam, or just cause legit server admins headaches...

Matt

[nickn]

Not sure why this is happening, but it's a huge problem on Yahoo's end... all of their mailservers seem to be greylisting (451 Message temporarily deferred - 4.16.50451 Message temporarily deferred - 4.16.50). I wonder if it'll actually cut down on spam, or just cause legit server admins headaches...

Matt

The mail daemons should handle it, very easy, receive a 451, try again in 5 seconds. whatever....Exim just isn't configured like that currently.

[NightStorm]

So nick, what do you suggest in terms of "quick hacks" to force Exim to send a retry a few seconds after a 451 error, then again 5 or 10 minutes later, and so on?
I haven't experienced the problem yet, since thankfully none of my users have tried sending anything to Yahoo... but I just know that sooner or later someone will, and I'll be stuck with this headache.
Best to plan in advance, ya know?

[fishfreek]

Please excuse my ignorance but how would I do as is suggested. COnfigure exim to automaticly attempt a retry on 451 errors?

Where would I specify this?

You can set a specific retry interval for the 451 error, which is what should be done (rcpt_451) something such as :

* rcpt_451 F,1m,3s; F,1h,5m; F,3h,30m;

[lloyd_tennison]

Yahoo has stated that the message is when their server is busy. I have not see anything that they say they have implemented greylisting - just that people are guessing that they have.

I have gotten those messages periodically for the last year or so, even with my server being whitelisted. The busy message is what they have told me, and it is usually when there is a new big virus out causing all kinds of blow-back to Yahoo.

You can contact them directly to find out why you are having all the 451 errors at their postmaster desk. My info from Friday is: I had with 2,131 451 errors with 250,000+ yahoo emails delivered on the first attempt. But then, maybe whitelisting bypasses it.

[fishfreek]

Well I have nearly 300 messages in my mail que from the last 48 hours all destined for yahoo accounts.

I have my system set to attempt to redeliver every 30 min. If what you say is correct that would imply their systems have been to busy to process the mail I am sending them for over 96 consecutive attempts for some messages. That of course does not include the attempted manual delivery times.

On the rare occasion I can manually push a message thru to yahoo via the deliver now link. Once one goes thru if I hit the deliver all link it comes back with the same number of messages as I started out with.

[cpdan]

We are looking into the best way to handle this:

http://bugzilla.cpanel.net/show_bug.cgi?id=4745

but its tough to say since yahoo doesn't even appear to be consistent:

http://www.emailbattles.com/2006/04/...aaddhghiad_ih/

That data at that url is pretty consistent with our tests, basically sometimes it 451's once then lets it go (greylisting) other times it 451's over and over for a long time.

If you'd like to track any updates we have about it please add your self to the CC list at the bugzilla entry above.

Thanks

[sparek-3]

I'm not sure if this is a greylisting issue. Perhaps other servers are seeing this differently. But it would appear to me that any of our servers that have a 4.16.50 error to Yahoo are just blacklisted and I don't know why.

The servers that I have that have a 4.16.50 error. If I connect once, wait 5 seconds and try to connect again, I'm still blocked. I sent a message to a yahoo address from an afflicted server last Friday, its still in the mail queue waiting to be sent to Yahoo.

Perhaps this is just me. Perhaps other users are seeing this as a greylist. I see this as a problem with Yahoo and not with cPanel.

Perhaps still my servers are justifiably blacklisted. Perhaps we have spammers on our servers. I don't think this is the case. I have not receive any other abuse complaints, and there's just too many people that are receiving 4.16.50 errors for me to consider this as an isolated legitimate spam/abuse issue on our servers, but I also won't say that its outside the realm of possibility.

One thing to note, the link http://www.emailbattles.com/2006/04/..._aaddhghiad_ih is referring to statistics gathered back in April of this year. While I have always had problems with Yahoo and connecting to their servers off and on, those problems were nothing along the scale of this current 4.16.50 error. And again, perhaps other people are seeing this error as more of a greylisting problem, but I don't think this current 4.16.50 error is the same as the connection problems from April. In previous connection problems, these eventually did clear up within a course of a few hours or a day at most. I would bet I am running close to two weeks on some servers that have been unable to connect to Yahoo mail servers.

[cpdan]

Perhaps this is just me. Perhaps other users are seeing this as a greylist. I see this as a problem with Yahoo and not with cPanel.

You're absolutely correct, and so far yahoo is silent but we are looking into ways of at the very least easing the problem as much as we can if possible.

Its actually multiple problems, greylisting being just one that is easily resolved but likely won't solve the problem complete since its a culmination of strangeness with yahoo.

Anything we find will be added to the bugzilla for anyone interested.

[lloyd_tennison]

Has anyone actually seen a place where Yahoo says they are greylisting? All I have seen are people guessing.

I had 12,600 emails sent by mailman to Yahoo today. (I did not count for any emails other than mailman. grep '=yahoo.com@mydomain.com".) I had only 25 "451" errors from Yahoo. Of those 25, all but one were for the same email address, one that has mail forwarded from my server.

I had no 421 errors today.

[DigitalN]

I've seen this with several isp's lately (optonline.net for one) that is giving this 'local system error - 451 or 452)

I put it down to the massive influx of spam within the past month, it has got worse the past week or so, so maybe they are mitigating the amount of email that hits their systems right now.. it seems to be a common problem, lots of isp's mail servers just cannot keep up with the input and have had to take evasive action.

[jester.ro]

i really think that trying to get around this problem by modifying exim retry times is the wrong approach.

if tousands of servers retry sooner than expected, yahoo will be hammered even more, and it might make things even worse.

yahoo is making a mistake by doing this, they shoukld work something internaly, maybe implementing a new queue system, so that if an email is considered legit, accept it and deliver it later.

[cpdan]

http://bugzilla.cpanel.net/show_bug.cgi?id=4745