Need help securing mail server: already got hacked.
I have exim4 using the heavy daemon set up and it runs fine. I am setting it
up to serve mail for 5 sites (all my own) that I have on a single box using
Apache2 and as virtual sites. All is working fine . I was advised that I
should set up a pop3 server in order to allow access from a remote system to
these mail sites. Again (I used popa3d) everything worked fine. The problem
is, I got hacked almost immediately and my mail system was used to send a
load of spam all over the place. The result is that I have had to shut down
the servers until I get my system hardened enough to do the job & quit
getting hijacked by spammers. I have been reading the docs but time is not my
friend here I need to get this done ASAP so I can get these servers turned
back on. My ISP will shut me down if I leave the system up in its current
state. All tips greatly appreciated.