Re: [exim] Matching $sender_host_address to MX for $sender_a…

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Author: Stephen Gran
Date:  
To: exim-users
Subject: Re: [exim] Matching $sender_host_address to MX for $sender_address_domain
On Sun, Oct 29, 2006 at 04:44:58PM +0100, B. Johannessen said:
> Stephen Gran wrote:
> > On Sun, Oct 29, 2006 at 03:48:25PM +0100, B. Johannessen said:
> >> Two of tests I'd like to try are:
> >> 1) Is the sending host an MX for the sender address domain?
> >> 2) Is the sending host in the same /24 as an MX for the sender address
> >> domain?
> >
> > This is a bad test.
>
> Did you even read the rest of my message? Is my English that bad? Just
> in case, I'll try again:


Yes, I read it. Sorry if I came off brusquely.

> I'm not going to used these tests to reject e-mail. I'm going to use
> them *not* to reject e-mail when other tests indicate that I should!


My point is that often there is absolutely no correlation between
sending IP address and MX information, even when the sending IP address
is legitimate. This is true whether you use it as a whitelist or
a blacklist. If you want published DNS information about what IP is
allowed to send email, there are infrastructures for that, although they
are poorly thought out or poorly implemented.

Good luck with it,
--
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|  Stephen Gran                  | You know it's going to be a bad day     |
|  steve@???             | when you want to put on the clothes you |
|  http://www.lobefin.net/~steve | wore home from the party and there      |
|                                | aren't any.                             |

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