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Problem sending emails to and fro China

Hi all,

I have encountered problems sending emails to China counterparts. However, i didn't receive any delivery failure mails that say mails cannot be send to China. I only got to know about the problem when my China colleague mentioned he didn't receive my mail. Anyone encountered similar problem and any solutions?
Many thanks!
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Aaron Street

8/22/2022 - Mon

Try telnetting on port 25 and manually create a session to see if you're able to connect to the mail server.
If you can, that ascertains that the problem is internal to the Chinese hosting system, and beyond your control.

How do i telnet on port 25 and manually create a session to connect to mail server?

Here's an example (with made up host names)

At the command prompt:
c:\>telnet mxmail.chinahost.cn 25

220 mxmail.chinahost.cn Microsoft ESMTP MAIL Service, Version: 6.0.3790.3
959 Ready at Mon, 14 April 2008 10:56:45 +0100
helo ind-tech.com
250 mxmail.chinahost.cn Hello []
mail from:bm@ind-tech.com
250 2.1.0 bm@ind-tech.com....Sender OK
rcpt to:administrator@chinahost.cn
250 2.1.5 administrator@chinahost.cn
354 Start mail input; end with <CRLF>.<CRLF>
Hello China
250 2.6.0 <chinahost25b6KZmcK8r6be0000000b@mxmail.chinahost.cn > Queued mail for delivery
221 2.0.0 mxmail.chinahost.cn Service closing transmission channel
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William Peck
Aaron Street

how about china has one of the most restrictive email/internet systems in the world. that is filtered by the goverment on all major back bones in and out of the country!

There is a lot of stuff that is blocked espicaly stuff from the west. and you wont get any information back about it..

I would say this is very lickley to be your problem.

I you can send mail every where else. then the problem is most lickly at chinas end and not yours.. Who are you sending to and from??

China is not quite as bad as places like IRAN, where up to 80% of web traffic if blocked by the goverment an only authorised content is allowd!


Yes, it's most likely that censorious e-maol policy is the cause of non delivery.

I tried to execute the command c:\>telnet mxmail.chinahost.cn 25 in command prompt, however it then turn out to be a blank screen. Any idea why?
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Please re-read my post.

mxmail.chinahost.cn is a made-up hostname. You have to substitute that with the actual mail host that you've been having difficulty sending e-mail to.


Are there any freeware that we can use to test the sending of email other than the one suggested of using command prompt?

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If you do not receive any undeliverable messages, there can be tons of reasons:
1. the recipient server does not generate undeliverable message;
2. your email might be treated as SPAM on the recipient server
3. the server/service is not available which happens to many ISPs, including Bell (however they have redundant service)
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William Peck
Aaron Street

I'm sorry

but the statment

"Also, China does not block any emails as there can be no way to block emails at all based on contents, address and header! If it is possible, the world will be free from SPAM"

Is completly wrong.. I have a huge black list. that filters out emails based on all of the above.
I can also block all network traffic based on what ever i want to block it on. IP address ranges, port ranges, data content, protical etc etc...

So I am sorry but that statment above is complelty misleading and in my view incorrect. How does the post actuly think SPAM filters work exactly?

Fine, China is able to block whatever she wants to block. I admit you are super genius and your view point is flawless.

Both of your posts here were wrong and/or irrelevant, including the e-mail address tool that was bizarrely accepted as an answer.
China does block whatever and whoever it wants, although it is less censorious than it was, partly because of the vast numbers of current and anticipated foreign visitors to the Olympics.
Sarcasm may reflect intelligence, but is still the lowest form of wit...
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Aaron Street

I'm sorry to upset you. But out of intrest how exactly do your spam filters work? or you fire walls? or you router access lists? Now the ones i have set up all block data on ip inforamtion, data content and many other bits of information related to the data they are monitering.

It is quite possible and easy to block say every request made to or from microsoft.com. This would block all web traffic, email, FTP, etc, etc.

And yes microsoft could get past my filter by renaming there domin microasoft22.com (this is why we dont get rid of spammers becasue they change there addresses and headder information as fast as we can block them)

Why exactly do you think it is not possible for china to do the same? (go to Iran and tell me there web/email is not restricted by there goverment)

Your statment about it is impossible to block date was wrong. So stop getting so upset, I wasnt being rude about it. But I was trying to teach the author of the question something, and making sure he understood the responces he has recived.

and if you still dont belive china blocks the web and email. try looking at
or just serching for china restricting web access in google..