Re: MailScanner/Exim

[Matt Cuttler <mcuttler@bnl.gov>]

Craig Sanders wrote:

> 5. configure exim on the backup MX to use that lookup to validate relay
> recipient addresses.


On both of these boxes, in your acl_smtp_rcpt, you could use something like:

##
accept hosts = +relay_from_hosts
endpass

(other rules (ratelimiting, etc) might go here here)..

verify = recipient
##

Obviously, you need to define your hostlist 'relay_from_hosts'.

This will stop bogus addresses at SMTP time.

Note: Having your MXes so willing to not accept mail at SMTP time does
leave you open to directory harvest attempts. You want additional ACLs
which log/limit unknown addresses.