Author: Renaud Allard Date: To: Dave Evans, exim-users Subject: Re: [exim] Blocking Users with No Reverse DNS
Dave Evans wrote: > On Mon, Nov 05, 2007 at 09:48:21AM -0600, Matt wrote:
>> Also, I heard some block IP addresses that look dynamic such as
>> 127.0.0.1.myisp.com. How is that done?
>
> Personally I do that with some Perl code, but I'd be interested to hear how
> other people do it (read: if nobody offers an elegant way of doing it, I'll be
> happier about sharing my inelegant code :-)
>
>
Here is a funny regex I use:
warn
set acl_c6 = ${lookup dnsdb{ptr=$sender_host_address}{${lc:$value}}
{}}
condition = ${if match {$acl_c6}{\N(^[^\.]*[0-9]\-+[0-9]|^[^\.]*[0
-9]{5,}[^\.]|^([^\.]+\.)?[0-9][^\.]*\.[^\.]+\..+\.[a-z]|^[^\.]*[0-9]\.[^\.]*[0-9
]-[0-9]|^(dyn|cable|dhcp|dialup|ppp|adsl)[^\.]*[0-9])\N}{yes}{no}}
log_message = Generic reverse DNS
delay = 30s
