I have to use a Win2k/Exchange 2k setup for our companies mail. There is no way to change or upgrade that. Due to various hacking & spam scenarios that played out, we implemented a linux based relay using qmail & perdition. That seemed to quell our primary issues however, now, a sender does not receive a bounceback when mail is sent to a non-existent user in our organization. I am certainly open to other (FOSS only) solutions but, am stumped so far. Here are our requirements:
- must have POP & SMTP access from the outside world using authenticated lookup
- must be mail relay in every since. In stays in, out goes out. No anonymous mailings.
- must integrate with 1 or more spam/rbl lists/groups for filtering
Ideally, I would just like to enable some type of AD LDAP or pop lookup on the same box so that when a user is not found it would bounce the msg back to the originator. I am having a difficult time finding a way to do this. I've thought of just performing a user dump for it to check against but, that can be cumbersome to keep updated everytime someone leaves the company. The current scenario performs a user lookup & if it doesn't find the user it just drops it.
Any suggestions ? Might there be another way to configure this better ? Maybe a different package would work better ?