Re: [exim] NDN, Mailer-Daemon, DSN - EXIM

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Author: Mike Brudenell
Date:  
To: Exim-users
Subject: Re: [exim] NDN, Mailer-Daemon, DSN - EXIM
Hello,

Be careful: it might not be 65*3 = 195 new SPF records that you need. It
might only be three! Remember that it is whatever your Exim (in this case I
think the Exim running on the server known as corp17.company.com) puts into
its HELO/EHLO command when it connects to another server.

By default this is the primary host name of your server, as set with
primary_hostname (or if you don't set it with this then the DNS name of the
server).

Looking back at your original question you say:

The Internal server for mass mailing:
primary_hostname = corp17.company.com and the qualify_domain = company.com


That means you're setting the primary hostname to "corp17.company.com" and
it's this that Exim always use in its HELO/EHLO when it connects to another
mail server. (But see the note below!)

That means you only need a new SPF record for the *corp17.company.com
<http://corp17.company.com>* domain name to correct that problem for that
entire mail server. You *don't* need one for every domain it happens to
send out emails from.

*Note:* The exception is if you use a *helo_data* command within your Exim
transport to set the HELO/EHLO string for each connection to, say, reflect
the domain name of the sender of the outgoing message instead of the
default action of always using the primary hostname. If you're changing the
value of the domain name in the HELO/EHLO greeting in this way then yes,
you'll need an SPF record for each domain name. (But then it would only be
65, not 3*65)

I suspect you'll only need 3 new ones in all, as most people don't use
helo_data to alter the HELO/EHLO greeting.

Cheers,
Mike B-)

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