On SMTP, putting the product sandwich-like between the same Postfix
This article describes how you can place F-Secure Internet Gatekeeper for Linux sandwich-like between the same Postfix.
Normally, the product listens to the connection and transfers e-mails to a specified parent server, such as Postfix. However, if you want to use the postfix feature related to the connecting source, you can place the product between the same Postfix server sandwich-like.
You can use Postfix's content_filter or smtpd_proxy_filter feature to put the product between the same Postfix installation.
An example of Postfix2.0 (using content_filter):
content_filter = smtp:localhost:9024
And to change myhostname on master.cf, add your domain name to "mydestination=" explicitly.
smtp inet n - n - - smtpd
9025 inet n - n - - smtpd
-o content_filter= -o myhostname=dummy.domain.name
Note: The above settings accept a connection to a port other than port 25 (9024,9025) directly. We recommend that you limit the connection to ports other than port 25 bu using firewall/iptables, or limit listening address to 127.0.0.1.