NSA 2400 - Exchange Server Cannot Send Emails Externally

MSP4ME

Hi All,

I was forced to prematurely remove an ESA3300 before we received its replacement. I was able to change the NAT rules to bypass the ESA and go straight to the server. I also removed the ESA's IP from Exchanges Smart Host.

I can Send emails and receive internally. I can receive external emails, but cannot send externally.

Not sure what I missed.

Any help would be greatly appreciated!

All the best,

Bill

Saravanan

Hi @MSP4ME,

Thank you for visiting SonicWall Community.

Are you unable to send emails from your exchange server via NSA 2400 appliance? If yes, please make sure the outbound NAT policy for translated source on the SonicWall is set with the IP address resolves to your exchange server's domain name.

If the NAT policy is correct, please perform a packet capture on the SonicWall appliance with destination port TCP 25 and we can identify the root cause of the issue.

Please refer below web-link as a reference and perform the packet monitor for your scenario.

https://www.sonicwall.com/support/knowledge-base/how-can-i-setup-and-utilize-the-packet-monitor-feature-for-troubleshooting/170513143911627/

Hope this helps.