Re: [exim] Problems with hichina.com mail servers?

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Autor: W B Hacker
Datum:  
To: exim users
Neue Treads: Re: [exim] Problems with hichina.com mail servers? - solved
Betreff: Re: [exim] Problems with hichina.com mail servers?
Frank S. Bernhardt wrote:
> Good day.
>
> This isn't really an EXIM problem but I'm not sure what to do.
>
> I have a customer that can't send e-mails to two of his suppliers in
> China in that his e-mails keep bouncing back with a '452 Invalid sender'
> messages.


Not spcifically so stated, but shall we presume that these come from your mail
server, and that it is an Exim MTA you are running?

If so - are you supporting what the destination needs if it does a sender verify
callout?

(extended logging should show at least a connection from them shortly after your
message hits the remote_smtp delivery phase).

Call that possibility ONE.

>
> I tried sending an email to the postmaster there and it bounced back with:
>
>> <postmaster@???>:
>> 218.30.103.130 failed after I sent the message.
>> Remote host said: 552 This user's disk quota exceeded, anyway you can
>> send a smail (<1KB) message to inform the person.
>
> The email was way less than 1K.
>


Different issue - not related to your problem.

> I tried a telnet to mail.promexsh.com 25 and as soon as I did:
>
> mail from: phil@???
>
> I immediately got the 452 error.
>


I'll call thei possibility TWO.

pintar.ca resolves to IP 209.250.128.44

but IP 209.250.128.44 resolves to webhost02.pathcom.com

The same telnet from one of my Hong Kong servers, HELO'ing with the hostname in
the rDNS, succeeds to the next step:

========

conducive# telnet mail.promexsh.com 25

Trying 218.30.103.130...

Connected to mail.promexsh.com.
Escape character is '^]'.
220-W E L C O M E T O H I C H I N A S M T P S E R V I C E !
220 mxvip2.hichina.com ESMTP server (quarkmail server - version 1.2.1) ready at
Thu, 20 Jul 2006 01:12:27 +0800

helo conducive.org

250 mxvip2.hichina.com Hello conducive.org

^]
telnet>
quit

221 mxvip2.hichina.com Out
Connection closed by foreign host.

========

Perhaps the distant end has an overly strict HELO match rule in place.

What happens if you try to HELO as webhost02.pathcom.com?

> This happens as well with the mail.jinmao.com server.
>


Likewise - it talks to a server with HELO / rDNS match:

========

conducive# telnet mail.jinmao.com 25

Trying 218.244.143.23...

Connected to mail.jinmao.com.
Escape character is '^]'.
220-W E L C O M E T O H I C H I N A S M T P S E R V I C E !
220 mxdxt3.hichina.com ESMTP server (quarkmail server - version 1.2.1) ready at
Thu, 20 Jul 2006 01:14:57 +0800

helo conducive.org

250 mxdxt3.hichina.com Hello conducive.org
^]
telnet>
quit
221 mxdxt3.hichina.com Out
Connection closed by foreign host.

====


> On further investigation I see mail.promexsh.com announces itself as
> mxvip2.hichina.com (218.244.159.32) and mail.jinmao.com announces itself
> as mxdxt3.hichina.com (218.244.143.23).
>


smtp banner aside, does your log show the same on actual incoming traffic?

> From the above I surmise that hichina.com has some serious problems or
> am I totally out to lunch (ok, I may be right and still be out to lunch
> but you know what I mean).
>
> Any constructive advice would be appreciated.
>


Well - they *may* be more strict about HELO/DNS match on arrival than they are
themselves on departure, and/or they use separate servers for incoming and
outgoing - not at all uncommon, and not always doen with the best of DNS
entries. The banner alone is not conclusive.

But if 'job ONE' is to just get your users' mail to be accepted by them, all you
*may* need to do is insure your rDNS and HELO match on your own server.

Easy to try that anyway.

HTH,

Bill