I have build up 2 virual machines on VMware. One with Ubuntu 8.04 server and the other one with Windows Server 2003 where I have installed and configured Exchange server 2003. On Ubuntu I have installed Postfix.

Now I want to test it and to integrate Postfix with Exchange. I have no idea how to do that. Regarding some researches what I have made on internet I saw that probably I need to transfer all users to Postfix, is that right?

While im telneting everything is ok.

My question is how to check if the mail what Im sending is filtering through Postfix? Lets say: mail naim@test.local want to send a mail to arifi@test.local and does that will filter through Postfix? In case if im sending a spam whould that be filtered by postfix?

I really would appropriate your help?

Hi blindmancries,

I'm guessing you want to use postfix as a mail gateway and to perform mail filtering. If your Exchange server is hosting mail for @test.local then an email from user1@test.local to user2@test.local will not be filtered.

The architecture would look something like this:

[internet]----[postfix]-----[exchange]

Only emails sent to or from the organisation would be routed through postfix ( if correctly configured ). Also, postfix will not be filtering by default, I suggest you add several other packages: clamav, spamassassin and amavisd-new.

The last time I implemented mail filtering gateways, the servers couldn't handle the load of filtering all the spam, I ended up using a policy daemon for postfix as well. Basically during the smtp connection, after the 'rcpt to: xxx@yyyy' command, postfix sends all the connection information to the policy daemon to make a decision on whether the connection is from a spam host or a valid mail server. Postfix will then allow or drop the connection before accepting the email. The servers now reject close to a million connections a day and amavis/spamassassin only needs to process the accepted emails.

good luck,

kbp

kbp

Yes you are right. I want to use postfix as a mail filtering. I want to filter mails what I'm getting to my mail server which is under Windows server (Exchange). I build up 2 virtual machines on VMware only for testing if Postfix will function before I'm implementing on my mail server.

I was thinking that mails wont be filtered if I'm sending emails from user1 to user2, but I wasnt sure. Could you please tell me how to solve this problem then. How to test if my postfix is working right.

Please, I need little bit more information.

Hi blindmancries,

First you need to configure a functioning set of relays:

Exchange needs to have the postfix servers listed in the SMTP connector 'smart host' field, this means that Exchange will relay all email sent outside the organisation via the postfix servers. (outbound)

The postfix servers need to be configured to accept email for the domain that Exchange is hosting eg. example.com, and forward it to the Exchange servers, this can usually be done with the /etc/postfix/transport file.
(inbound)

The postfix servers need to be configured to relay mail for the Exchange servers, usually the 'mynetworks' directive. (outbound)

With proper name resolution configured, this setup should allow email to flow into and out of Exchange.


The next major piece of work is configuring filtering in the postfix system, unfortunately this is a complex process and to save my fingers I'm going to suggest a bit of reading, you could possibly start here:

http://www.lxtreme.nl/index.pl/docs/...tent_filtering

I can provide you with a working configuration but I recommend you try it yourself first, you'll gain a greater understanding and you may come up with a better config

enjoy,

kbp