Delivery delayed to Chinese domains

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blopam
Posts: 8
Joined: Tue Oct 15, 2013 10:19 pm

Delivery delayed to Chinese domains

Post by blopam » Tue Oct 15, 2013 10:30 pm

Hello, our email server works great, except for some messages we send that get a delivery delayed notification like the one I paste below.

Our problems are only with Chinese domains.

Our server is hosted in Canada.

Any ideas?

==================================
SAMPLE DELIVERY MESSAGE
==================================
De: Delivery Subsystem [mailto:POSTMASTER@ourdomain.com.mx]
Enviado el: martes, 15 de octubre de 2013 10:49 a.m.
Para: example@ourdomain.com.mx
Asunto: Message Delivery Delay


MailEnable: Message delivery has been delayed.

Message is waiting at ourdomain.com.mx for delivery to
163mx03.mxmail.netease.com.

The message will be retried for another 30 hours.

Reason: ME-E0029: [F00A723012E23AAD84262D12FA3465.MAI] DATA Command
Failed. Transmit File: Communications Error Transmitting File to 163.com.

blopam
Posts: 8
Joined: Tue Oct 15, 2013 10:19 pm

Re: Delivery delayed to Chinese domains

Post by blopam » Tue Oct 15, 2013 10:55 pm

More information from the logs:


10/15/13 10:48:45 ME-I0026: [F00A7230122F44A9AD84262D12FA3465.MAI] Sending message
10/15/13 10:48:45 ME-IXXXX: [F00A7230122F44A9AD84262D12FA3465.MAI] DNS resolved to the following record: IP Address=220.181.14.158, Family=2, Type=1, Protocol=6

10/15/13 10:49:28 ME-I0009: [F00A7230122F44A9AD84262D12FA3465.MAI] Remote server has closed connection after 30016 milliseconds. Server Response: (-)
10/15/13 10:49:28 ME-I0009: [F00A7230122F44A9AD84262D12FA3465.MAI] Remote server has closed connection after 0 milliseconds. Server Response: (-)
10/15/13 10:49:28 ME-I0147: [F00A7230122F44A9AD84262D12FA3465.MAI] DATA command returned network error - -.
10/15/13 10:49:28 ME-E0029: [F00A7230122F44A9AD84262D12FA3465.MAI] DATA Command Failed. Transmit File: Communications Error Transmitting File to 163.com.
10/15/13 10:49:28 ME-E0033: [F00A7230122F44A9AD84262D12FA3465.MAI] DATA Transmission failed.
10/15/13 10:49:28 ME-E0048: [F00A7230122F44A9AD84262D12FA3465.MAI] - Transmission errors occurred during delivery. Message has been re-queued.
10/15/13 10:49:28 [F00A7230122F44A9AD84262D12FA3465.MAI] caused a Delay Message to be generated with a Message ID of [C2882DC9AAE25A300145B907D6089.MAI]. The recipient of the delay is: example@ourdomain.com.mx

dbly
Posts: 47
Joined: Wed Aug 20, 2008 9:18 pm

Re: Delivery delayed to Chinese domains

Post by dbly » Wed Oct 16, 2013 6:53 pm

You are being tarpitted/greylisted by the recipient server. If you are getting "Message Delayed" and not "Message Failed" then things are working as they should, and the messages are getting through.

There are things that you can do on your end to decrease the likelihood of being delayed in this fashion, but that depends a lot on how you are set up, who you have for your ISP, your forward and reverse DNS, SPF, DKIM, etc. If you turn on Debug logging you will have a better idea at what point during the session things start slowing down, it is important do determine whether it is before or after the HELO, and before or after the RCPT commands, before or after the DATA command, etc. In the end, however, remember that you can't control their server or what they do on their end to handle capacity or combat spam.

blopam
Posts: 8
Joined: Tue Oct 15, 2013 10:19 pm

Re: Delivery delayed to Chinese domains

Post by blopam » Thu Oct 17, 2013 10:38 pm

Hello dbly, thanks for your response. Actually those are the debug logs.
What you say confirms my suspicions. Everything is fine on our side, the problem is on the other side. I'll keep investigating, thanks a lot, take care.

dbly
Posts: 47
Joined: Wed Aug 20, 2008 9:18 pm

Re: Delivery delayed to Chinese domains

Post by dbly » Fri Oct 18, 2013 3:13 am

Yes, I mean the activity log. That's where you will see the CONN/EHLO/etc. commands.

I assume you have already done all of the basic things - making sure that you have a reverse PTR record pointing to the ip address of your mail server, making sure that there is a matching forward DNS entry that matches the reverse DNS, established SPF records in your DNS, etc. Have you enabled DKIM signing yet?

aahq
Posts: 183
Joined: Sat Aug 07, 2010 11:08 am

Re: Delivery delayed to Chinese domains

Post by aahq » Sat Oct 26, 2013 11:16 am

Though you are in Canada it may be worth considering paying a third party vendor like SMTPCORP to deliver your mail for you. A second option may be to change ISP's delivering your mail. Maybe even have a look at MXToolbox.com to see if it can give you some hints on why others are having trouble with your email delivery. They may have a lot of spammers on their network, which is dragging their "reputation" down. It seems these days if you live in a bad neighbourhood on the net you are classed the same as all the vagrant mail servers.

Scott

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