I try to publish my internal SMTP server.
My ISA server has a nic on the internet and another one on my LAN.
I added a 'Server Publishing rule' on ISA such as : * Action : * Internal server : 192.168.1.1 * External IP of isa : 10.1.1.1 * Mapped server protocol : SMTP Server There is also a 'Protocol Rule' * Action : allow * Protocol : SMTP * Schedule Always * Appky to any request
Port 25 is now opened on ISA external nic. When I 'Telnet' it I get the connection, but then nothing. Helo does not work.
If I do the same thing on my internal SMTP server it works fine.
I also used some 'command line' SMTP tools and get the same problem (does not work on ISA external nic, works on SMTP server).
Do you have an idea of what is going on ?
I have just done a netmon trace. When my ISA talks to my SMTP server, the source IP adress is its 'external IP Address' (it sould be the lan one !) and destination is the 'internal Ip address'. The problem (I think) is that my SMTP servers does not know the 'external IP Address' (of course).
If you server publish an internal resource, that resource should be configured as a SecureNAT client. That means that his default gateway should point to the ISA internal interface.
By default, ISA don't translate the source IP address for inbound traffic in server publishing, because ISA is not really terminating the connection as is the case with web publishing (reverse proxy). However, you can change that behaviour if you like. Check out http://support.microsoft.com/default.aspx?scid=kb;en-us;311777 for more info.