what tool to use for smtp checking?

[dino]

hi there,
I want to set up a linux system between a firewall and a complex system of viruswall, spambox and mailserver. The only thing the linux machine has to do is checking the inbound smtp stream:
if the recipient is not listed as an employee than the connection has to be terminated (or the mail deleted). If the recipient is listed than the mail has to be forwarded to the next station. The list of the employees can be a text list or (that would be the perfect) from the already running ldap server.

can anyone give me some clues to do this?

thanks in advance
dino

[Giro]

You should be able to do this using you MTA which you have not metioned.

EDIT :- Do you catch all mail if so dont you will get a ton of crap. And i dont get it your MTA should drop it as soon as it know it is an invalid user unless you are catching all mail.

[dino]

in the mx record is the ip adress form the first firewall (a windows system).
this machine can not validate if the to: recipient is valid.
the firewall then routes the mails into the dmz to a viruswall (windows again)
the next station is a orange box (spamwall) (another windows)
and the last station is a domino r5 server which can validate a user. but on this station is it too late to check. i want a non-windows system in a first (or second) place only to check for a valid user.

the functionality of this linux machine is only to check incoming smtp mails against a text list containing valid recipients. i think there must be some mail tools to do this but my experience with mailrouting (or tools) in linux is minimal.


best regards
dino

[Giro]

Why not use one machine in the DMZ to do virri/spam/mail instead of a long line of machines?? Clam AV and spamassin comes to mind.

[dino]

i agree with you 100% but unfortunately i cannot change the long line of systems. the only possibility i have is to bring in a system between the first firewall and the DMZ.

dino

[big_k105]

will either of these beable to help you out any?

http://emailrelay.sourceforge.net/

http://assp.sourceforge.net/

i dont know if they will i was jst looking around on sf.net searching for email redirector and seeing if that would help you or not. if none of these help and you cant find something i would think it wouldnt be that hard to write a program that would do this for you hope this help

[dino]

i try this out and give you a comment of the result.

thanks for now.
dino