No subject

(it's probably easier to understand it by viewing the web page rather 
than reading my cut & paste)

"OK, now we are in the bear pit. We need to add a couple of definitions at 
the top of the exim.conf file as follows :

Code block

hostlist filter_relays = net-lsearch;/etc/filterrelays : 
net-lsearch;/etc/relayhosts
domainlist filter_domains = lsearch;/etc/filterdomains


Then, we are looking for the check_recipient: block and shortly after that 
there should be a line :

accept  hosts = :

Then, following this line, you can add the following :
Code block

deny
!hosts = +filter_relays
domains = +filter_domains
message = Please use the proper domain MX record"