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List:       postfix-users
Subject:    Re: send different EHLO greeting for different domains
From:       mouss <mlist.only () free ! fr>
Date:       2007-09-30 13:21:54
Message-ID: 46FFA2F2.8050209 () free ! fr
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Sebastian Reitenbach wrote:
> Hi,
> 
> my mailservers name is 48.53.204.212.ediscom.de, well, the hostname looks a 
> bit dynamic, but it isn't.

It doesn't matter. What matters is that is has a genric rDNS, and as
such, is a good candidate for blocking at many places. It's zombie fight
these days, you know...

Try asking for a meaningful rDNS if this is possible.

> I configured postfix to use this name in 
> myhostname and so forth, and therefore it uses it in the EHLO greeting. I 
> just recognized that when sending mail to hotmail.com, then the connection 
> is immediately dropped after my server sent the EHLO greeting. 

and sites using spamassassin will get your mail tagged as spam unless
you trigger no other rule but the dynamic ip helo one...

> I changed the postfix myhostname to mail.l00-bugdead-prods.de (an alias of 
> the above name) and hotmail accepted the mail for delivery. 
> This seems to be fine for hotmail, but I know this will get me in trouble 
> with lots of others mail servers.
> 


but

# host mail.100-bugdead-prods.de
Host mail.100-bugdead-prods.de not found: 3(NXDOMAIN)

you need to add an A record (212.204.53.48) for this name. (IP(helo) =
client_ip makes your helo identify the host, so your helo is more than
compliant).

> Do I can configure postfix to send different hostnames in the EHLO greeting 
> for different domains? 

while you could see the hotmail case, some sites may just discard your
mail (or put it in a Junk folder never checked by users, given the
number of spam there). so add the correct A record for mail.100.* and
use this for all your mail. use this name as myhostname for example.

That said, consider asking for a "meaningful" rDNS.

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