Re: [exim] Detecting the domain part of a host address

Philip Hazel wrote:
> On Mon, 25 Jun 2007, Marc Perkel wrote:
>
>
>> What would be the method of detecting the domain part of a host address?
>> For example:
>>
>> 82-46-151-246.cable.ubr04.perr.blueyonder.co.uk
>>
>> How would you write an ACL that would extract the blueyonder.co.uk part?
>>
>
> I think the point several people have tried to make is that you can't in
> general do this kind of thing without knowing something about the
> DNS domains and zones. Can you guess by inspection what the "domain" (in
> your meaning, I'm not quite sure exactly what that is, I think you might
> mean zone, but maybe not) is for these names:
>
> mx.cam.ac.uk
> virgo.cus.cam.ac.uk
> ewe.damtp.cam.ac.uk
> www.cl.cam.ac.uk
>
>
What I want is to extract the cam.ac.uk part of the above names. It's
the TLD + the first string immediately before the TLD.