Re: [exim] Detect missing reverse dns

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Author: Ian P. Christian
Date:  
To: Todd Lyons
CC: Exim Mailing List
Subject: Re: [exim] Detect missing reverse dns
2009/7/18 Todd Lyons <tlyons@???>:
> Makes sense, that verbage about fail didn't quite make a distinction
> to me about when to use it the first few times I read it, I'll read it
> again and see if I can understand the context to use it.



I urge you, and everyone else running an MX to just outright reject
mail from hosts without rDNS - there's no excuse for mail server
admins not to do this, and people not being strict means spammers can
get away with more on botnets.

The stricter we all are, the better.

We use this:

  deny
  ! condition      = ${lookup dnsdb{defer_never,ptr=$sender_host_address}{yes}}
    log_message    = [RDNS] no PTR found for $sender_host_address
    message        = This host has no reverse DNS, See \
                     http://postmaster.timico.net/faq.html#RDNS for
more information.


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