Re: [exim] RDNS lookup failures...

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Author: Mike Cardwell
Date:  
To: exim-users
Subject: Re: [exim] RDNS lookup failures...
* on the Fri, Mar 09, 2007 at 07:49:46AM -0600, James Price wrote:

> My 2 cents to clarify.  I want to only deny based on Mike Cardwell's #1:
> 1.) No reverse DNS
>     - This tells me that the source probably shouldn't be sending mail,
>       or has been configured incorrectly

>
> As for the small business issue. I'm not denying based on whether the a
> record matches the reverse, only if the IP has a ptr record. Most ISP's
> these days from small to very large follow a standard protocol of
> 123-456-789-890.ip.domain.com in many cases for dynamic addresses as well as
> static assignments. Further if you simply request from your ISP, most will
> change the RDNS to match whatever you want.
>
> That all being said, I just want to deny based on if there's a ptr record
> for a given IP, not if it matches the a record.
>
> Mike thanks again for a good tip.


No problem. Bugs me when I see an exchange like:

Q.) How do I do this?
A.) You shouldn't do it

When it should be:

Q.) How do I do this?
A.) Like this. But here's some reasons why I think you shouldn't.

> Should I lose the host_lookup = * in the beginning of the config?


I'd leave it on if I were you. It puts more useful info in the exim
logs. It makes no difference whether or not you have it turned on
though with regards to your original question, and my solution.

Mike