Re: [Exim] Using IP address in dnslists check

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Author: Philip Hazel
Date:  
To: James P. Roberts
CC: exim-users
Subject: Re: [Exim] Using IP address in dnslists check
On Wed, 31 Dec 2003, James P. Roberts wrote:

> **********
> 38.14. DNS lists keyed on domain names

                   ^^^^^^^^^^^^^^^^^^^^^


Note that this is different from DNS lists for IP addresses.

> tld.example.dsn.rfc-ignorant.org
>
> I am confused by the doc. The example address looks
> backwards, as the tld is normally at the end of a
> valid address.


My bad usage of "tld". Should be something else.

> As I understand DNS lists (RBLs), one usually submits
> a request using a **reversed** dotted string with
> the list domain appended.


That is true for traditional DNS list lookups for IP addresses. It isn't
true for the newer domain-based lists.

> My question is, if I want to check IP 1.2.3.4
> against a dnslist, in an ACL, do I use:
>
>    dnslists = cbl.abuseat.org/1.2.3.4
> or
>    dnslists = cbl.abuseat.org/4.3.2.1
> ?


Aha! You are trying to subvert the feature for lookup up by domain
names, and use it for looking up an IP address. In that case you will
have to do the inverting yourself.

> If Exim does NOT do the inversion; then, although
> the doc is technically correct as is, it is
> confusing to see tld first in the example address.


True. I should revise that documentation.

Philip


--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book