[Pkg-exim4-users] adding custom filters

[Robert Keyes]

I've recently outsourced spam filtering. I have to pay per domain and per 
user, so the domains I host for friends aren't serviced by the spam filter 
service. I don't want spammers to be able to bypass the spam filter 
service and send mail directly to my server. I found that other people 
have had similar needs and exim was able to satisfy them, but the 
configuration posted was for a generic exim4 setup and not with Debian's 
specific configuration. I've broken things in the past messing around with 
configuration files, so I am wondering if someone can tell me precisely 
what I need to change to get this recipie to work. (Debian stable, unified 
config file).