CyTekHosting - News/Updates/Blog

Yahoo Issues Resolved, Spam filters

Fri, 27 Feb 2009 9:37:00 PST

I've been checking on the mail queues a few times a day, and would like to report that the fix I applied (and talk about in the previous yahoo blog) worked like a charm, and the queues are empty. Yahoo emails are getting through finally. BUT, please still email to yahoo with care, avoid sending too many emails at once, as they are delayed by 5-10 minutes per email. If you or your remote yahoo users are noticing a delay in delivery to yahoo still, this is most likely why.

On another topic, I had made some adjustments to the spam filtering system a few weeks ago, and am happy to report, our spam flow has dropped drastically since. The spam flow has gone from several thousand a day (at least), down to under 100 (estimating). My box email (which has many many emails and domains attached to it) used to get around 1000 spam messages a day. Today, my spam folder is empty.

If anyone has questions/comments/problems with the spam filtering modifications, or the yahoo issue and its resolution, feel free to email me, using the email link at the top.

Yahoo Email Delivery Issues : Updated

Fri, 20 Feb 2009 8:27:00 PST

I wanted to update everyone on the current yahoo status. Yahoo is still slow to deliver and should still be avoided if possible, but things are getting better (from my own efforts, yahoo has not helped us one bit). Delays are reducing, and queued emails are starting to get through.

-- DETAILS --

I am providing these details, error messages and info, for other hosting administrators and mail services to learn from our efforts.

Yahoo has not responded to the last submission/request at all. However, since the proper channels of communication have failed, repeatedly, I have taken matters into my own hand. After hacking away at our mail servers source code, applying custom patches, mods, etc, I have finally had a breakthrough. Instead of letting yahoo throttle how fast we send emails to them, instead we are now throttling the delivery speed on our end.

Here is what yahoo does, on connection, when they are blocking:
# telnet c.mx.mail.yahoo.com 25
-Connected to c.mx.mail.yahoo.com.
-421 Message from (70.99.205.15) temporarily deferred - 4.16.50. Please refer to http://help.yahoo.com/help/us/mail/defer/defer-06.html
-Connection closed by foreign host.

They don't even let us start sending an email before they reject.

-- The solution --

The patch we applied, is a wrapper for qmail-remote. It makes use of a new file called /var/qmail/control/remoteratelimit, which contains a file with domains and time limits per email, example "domain.com:600". This was the easiest approach, as it requires minimal source editing, just make sure permissions are correct.

My /var/qmail/control/remoteratelimit settings:
1) I started with yahoo.com set to 4 1/2 hours, via a line that looks like this, w/o quotes: "yahoo.com:16200"
This setting will allow 1 email to yahoo every 4 1/2 hours. This allows yahoo to "cool off" and lower the negative reputation score.
2) After a day or so, manually test connection to yahoo's server, via telnet, as done above. Yahoo has multiple mx hosts, so you don't have to use c.mx.mail.yahoo.com , they have "a.mx...." and "b.mx..." etc. However, they all seem to be tied together when they block, so if ones blocked, they most likly are all blocked.

   2a) If that was successful, which it should have been, lower your time in half every day, until you reach 600 (10 minutes per email). This seems to be the sweet spot, as our issues are clearing up nicely.

   2b) If this still fails, check to make sure you installed the patch correctly, make sure you created the "/var/qmail/control/lastdelivery" folder, and make sure qmail can write to it (user=qmaild, group=qmail, perm = 775). This folder is used to keep track of the last delivery times, and if setup properly and email is going through to the specified hosts, should contain files, named after each domain,(ie yahoo.com) and will contain a timestamp of the last delivery. If you want to reset the last time, simply delete the file (lastdelivery/yahoo.com for example).

The Details/Script/Code are buried in this forum, Post #14, by frob-qmail at webcentral:
http://www.gossamer-threads.com/lists/qmail/users/121426

Help Doc: IMAP over SSL for Outlook Express/Thunderbird

Mon, 16 Feb 2009 17:40:00 PST

I have posted a guide on how to configure IMAP over SSL for Mozilla Thunderbird and Microsoft Outlook Express.
http://cytekhosting.com/help_docs/

NOTE ABOUT OUTLOOK EXPRESS: Outlook express does not provide a way to "remember" your settings when it comes to the SSL certificate. We are working on getting a valid one generated and plugged in to the mail servers, until then, it will pop up warnings about the certificate being self signed. Thunderbird has the option to "remember" when you choose to accept the certificate.

Implementing additional spam filtering/features

Thu, 12 Feb 2009 23:47:00 PST

We're in the process of adding additional features to our spam filters, including better blacklisting support, better spam flagging, and more.

Yahoo Email Delivery Issues

Fri, 6 Feb 2009 14:38:00 PST

I would like to take a moment to alert everyone of the yahoo issues, and the current status.

Yahoo has been delaying/rejecting emails from our server for the last several months. Until we get the issue resolved, please avoid emailing people at their yahoo addresses if possible, as it only delays it further. Thank you for your patience during this process.

--- RANT ---

When the issue first arose, I immediately took action to contact them, to request a white listing, or to at least be provided with details as to why they are blocking us. After filling out 5 separate forms and getting the same 2 template email replies, which i fill out and send back, and they reply with one of the 2 template email replies.

I am beginning to think that there are no humans working at yahoo's email support dept. Upon further research/investigation, I found that there are a plethora of small hosting companies experiencing the same "cold shoulder" from yahoo. Some even suggested a class action lawsuit... but lets not go there yet.

I filled out the form again a few days ago, and surprise surprise, I got the good ole template email, that asks me for the same information I provided when I filled out the form... So I jump through another hoop and fill it out, and send it back, and I'm still waiting for a reply...

Meanwhile, I've programmed some alternative fixes, that are being implemented throughout the week/weekend.

Email Encryption - IMAP/POP3 over SSL support!

Thu, 22 Jan 2009 19:09:00 PST

We've added IMAP over SSL support for both of our mail servers. There were a few minutes of email downtime during the launch, but services were quickly restored.

I will be releasing a guide shortly, on how to enable secure email reading for several common email clients, such as Thunderbird, and Outlook Express. (Basically, you enable IMAP over SSL, which defaults to port 993. NOTE: We don't support "Secure Password Authentication", because with IMAP over SSL, its unnecessary.)

Blog Created

Thu, 22 Jan 2009 18:47:00 PST

CyTekHosting has launched a new blog, to help keep our customers more closely updated about planned outages, upgrades, and more.