Re: [exim] blocking on failure of reverse_host_lookup

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Autor: Mike Cardwell
Fecha:  
A: Exim Users List
Asunto: Re: [exim] blocking on failure of reverse_host_lookup
Joan wrote:

> I set up rdns checks enabled by default, the ip addresses that doesn't
> have a valid rdns get a 450 temporary error.


Can I ask why you respond with a temporary error rather than a permanent
error message? By doing that it just seems that when you block a
legitimate email, the sender doesn't find out until much later... At
least with an immediate permanent rejection the sender knows that their
email didn't get through as they should get a bounce straight away...

> I created a big whitelist for the neighbour countries grouping the ips
> in big ranges.


FYI, if you want to apply "country" based rules to incoming connections,
there are dnsbl's that map IPs to countries. Eg, to accept mail from
hosts in the UK and France:

accept dnslists = uk.countries.nerd.dk : fr.countries.nerd.dk

countries.nerd.dk also let you download their full data set in rbldns
format (and other formats I think) so you can create your own local dnsbl.

--
Mike Cardwell - IT Consultant and LAMP developer
Cardwell IT Ltd. (UK Reg'd Company #06920226) http://cardwellit.com/