Mailing List CGatePro@mail.stalker.com Message #91738
From: Wael Shahin <wael.shahin@gmail.com>
Subject: Re: "we refuse to relay" and MX
Date: Thu, 12 Jul 2007 11:04:58 +0300
To: CommuniGate Pro Discussions <CGatePro@mail.stalker.com>
X-Mailer: Evolution 2.10.1
Hi,

On Wed, 2007-07-11 at 20:26 +0200, Andre Mueller wrote:
> Hello
>
> As our secondary MX server received a lot of spam mail with destination
> to our mail-server

Spammers are not following standards whatsoever, and they don't care
what priorities you have for your MX records, they rather tend to send
to the server that accepts emails the most.

>  I altered today our MX entries with a third MX server
> pointing to our primary MX server:
>
> @               IN      MX      10      mail.our-mail-server.com.
> @               IN      MX      20      mail.secondary-mail-server.com.
> @               IN      MX      30      mail.our-mail-server.com.

This kind of setup is not recommended. it might be pain for your mail
server and DNS serevr before it does to others

> On our CommuniGate-Server we have several domains and have been used to
> use for different accounts on our mail client (thunderbird) only one
> outgoing smtp-configuration with authentication:
>
> me@domain-one.com -> standard smtp-server : my@domain-one.com
> me@domain-else.com -> standard smtp-server : my@domain-one.com
>
> Now after altering today our MX entries with the additional third MX
> server entry we receive from certain destination mail-servers/domains
> the error message "we refuse to relay" when we send emails from the
> account me@domain-else.com.

A strictly configured server would most probably fail connections from a
domain that has duplicate MX records. This is a false positive.

> Changing the email-client account
> configuration to the following, emails to the refusing mail-servers are
> accepted:
>
> me@domain-else.com -> standard smtp-server : my@domain-else.com
>
> As we have on the same server CommuniGate is running on also some
> web-applications on the behalf of some customers, emails generated from
> these web-applications are sent out by our CommuniGate server. The
> web-applications do smtp authentication on our CommuniGate server on
> corresponding accounts but have "from" and "return-path" with different
> email-addresses:
>
> web-application will send out by account customer@domain-one.com and has
> as "from" email-address web@customer.com. Before the
> alteration/modification of the MX entries today also these email were
> accepted on other destination mail-server without no complaints. After
> the alteration on the MX entries of today, emails from the
> web-applications are refused with the returning message "we refuse to
> relay".
>
> In the short I would like to ask, how a third MX entry is related to the
> delivery/relay acceptance in general and if there is any way to get the
> intended purpose of a third MX entry (to avoid that spam is directed
> over the secondary MX) and email can be sent out with a different "from"
> and "return-path" in the email header?
>
> Many thanks in advance and with best regards, André
>
>
>
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