@jorge:

xmailer looks like a good mail solution, but it's loaded with features 
I do not need. I will try xmailer in another project ;-)

@Michael
Well, NAT'ing is okay, but some people don't like their mailservers to 
be exposed to the world in any way.

I'll take a look at ssmtp.


So far, I've found "spammer deterrent" from http://sd.inodes.org/ . It 
has some anti-spam features but it's lightweight.

MfG
Peer