SonicWALL 8000 User Manual

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Given this:

10.100.0.10: Exchange Server (exch1.example.com)

10.100.0.100: SonicWALL Email Security appliance (esa.example.com)

You might have two paths that look like this:

          Source IP    Listen On  Destination

Inbound   Any          Any:25     (proxy) exch1.example.com:25

Outbound  10.100.0.10  Any:25     MX

In this scenario, any message that arrives at the SonicWALL Email Security appliance 
from 10.100.0.10 will be treated as an outbound message, handed off to the MTA 
component in the system, which will deliver the message via MX-lookup on the domain 
in the TO field. Messages that arrive at the SonicWALL Email Security appliance from 
any other IP address will be treated as an Inbound message, and delivered directly to 
the Exchange server. The SonicWALL Email Security appliance always gives preference 
to specific matches (for example an exact IP address match takes precedence over 
“Any”).

Another example using port numbers to distinguish which path a message should take:

          Source IP  Listen On  Destination

Inbound   Any        Any:25     (proxy) exch1.example.com:25

Outbound  Any        Any:

2525

   MX

Another alternative would be to assign your SonicWALL Email Security appliance 
multiple IP addresses, and have it listen on one for inbound and one for outbound.

In all of the above cases, the admin will configure Exchange to deliver outbound email to 
the IP address and port number where the SonicWALL Email Security appliance is 
listening for outbound mail.

To test your SonicWALL Email Security appliance, click the Auditing button at the top of 
the SonicWALL Email Security appliance user interface and search for your sent email to 
verify it has been sent and received.