Re: [exim] only allowing certain IPs based on domain name

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Author: Dave Evans
Date:  
To: John Cage
CC: exim-users
Subject: Re: [exim] only allowing certain IPs based on domain name
On Thu, Jan 03, 2008 at 11:09:20AM -0800, John Cage wrote:
> We're using an external spam filtering company for some of our domains (but
> not all). They have provided us with the IP addresses that their servers use
> and have suggested that we allow incoming mail from these addresses, but
> block all other - but only for these domains (obviously). I've searched for
> this, but in vain, and any help would really be appreciated


So do the MXs for those domains point to this other spam filtering company,
not to you? And then they deliver the mail to you based on some nominated
hostname (i.e. not MXs)?

If so, DNS TTLs permitting, you'll want to permanently reject (deny) attempts
by others to send mail to those domains. In general, something like

  deny
    domains = somedomain.example.com
    hosts = !spamfilteringserver.example.net
    message = Relaying denied


placed appropriately in your RCPT ACL should do the trick. For more
information, read
http://www.exim.org/exim-html-current/doc/html/spec_html/ch40.html#SECTaclconditions ,
especially "domains = <domain list>" and "hosts = <host list>".

--
Dave Evans
http://djce.org.uk/
http://djce.org.uk/pgpkey