Wolfgang.Fuertbauer@??? wrote:
> Hello,
>
> exim receices all mail comming from the internet and after virusscanning,
> ... forwards
> it to an lotus domino server;
>
> recently i get *tons* of faked emails (sender claims to be from our domain,
> recipient is
> combination of chars and numbers in localpart, for example:
> 4edre57887@???)
>
> my question is:
> how can i configure exim to do a recipient verification on the relay host
> for all
> incomming messages ?
Either, you save all possible addresses on your mailhub (with some cdb
database or something similar) that would make it possible to use
something like this in your acl:
require domains = +relay_to_domains
recipients = cdb;/etc/exim/knownrecipients.cdb
OR, you're keen and do recipient verification with callouts. With the
callout-cache since exim4.11 this shouldn't be a big problem to your server.
require verify = recipient/defer_ok/callout=10s/callout_defer_ok
You'll will need the defer_ok settings, otherwise your backup is useless.
Nico
