Custom HELO/EHLO response

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Custom HELO/EHLO response

Daniel Ryšlink
Hello!

When a postfix server replies to the HELO/EHLO command, the response
starts with this line:

250-mail.dialtelecom.cz

However, when Exim or other server replies, the first line contains
additional information:

250-mx01.dialtelecom.cz Hello office.dialtelecom.cz [212.24.132.66],
pleased to meet you

I would like to know if there is a way to customize this reply in
Postfix, specifically, if there is a way to include the information
about the sender IP and reverse DNS name as in the second reply via
modifying Postfix configuration, and if it is possible, then I would
like to know which configuration directives should be used.

I thank anyone in advance for any useful information, and I apologize in
advance if my question does not adhere to a required standard, or if the
question seems trivial. I did look through the Postfix documentation,
and I also looked through all the postconf configuration directives in
the active configuration of my server, but I did not find anything
relevant.

--
S pozdravem,
Daniel Ryšlink
System Administrator

Dial Telecom a. s.
Křižíkova 36a/237
186 00 Praha 3, Česká Republika
Tel.:+420.226204627
[hidden email]
-----------------------------------------------
www.dialtelecom.cz
Dial Telecom, a.s.
Jednoduše se připojte
-----------------------------------------------

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Re: Custom HELO/EHLO response

Ralph Seichter
On 01.09.2017 15:48, Daniel Ryšlink wrote:

> I would like to know if there is a way to customize this reply in
> Postfix [...]

See 'smtpd_banner' and 'postscreen_greet_banner'.

-Ralph
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Re: Custom HELO/EHLO response

Viktor Dukhovni
In reply to this post by Daniel Ryšlink
On Fri, Sep 01, 2017 at 03:48:21PM +0200, Daniel Ryšlink wrote:

> When a postfix server replies to the HELO/EHLO command, the response starts
> with this line:
>
> 250-mail.dialtelecom.cz

Via the smtpd_banner parameter you can replace this with any *fixed*
string.

> However, when Exim or other server replies, the first line contains
> additional information:
>
> 250-mx01.dialtelecom.cz Hello office.dialtelecom.cz [212.24.132.66], pleased to meet you

This is mostly pointless.

> I would like to know if there is a way to customize this reply in Postfix,
> specifically, if there is a way to include the information about the sender
> IP and reverse DNS name as in the second reply via modifying Postfix
> configuration, and if it is possible, then I would like to know which
> configuration directives should be used.

There is no current mechanism to inject client-specific data into
the SMTP server banner.  Is there a good reason to add such a
feature?

--
        Viktor.