Why is my IMAIL IPswitch server closing port 25 connections from my Barracuda Spam Firewall?
Date changed: 4 years ago
Scope: Applies to all Barracuda Spam Firewall customers using an IMAIL IPswitch email server.
Answer: There are built in SMTP access controls on the IMAIL server. Please check the rules listed for the following rule and verify there aren't any IPs listed with an "Allow all except clause":
SMTP Access Control.
The SMTPD service checks if the connecting IP is listed in the Access Control dialog box. If it is listed in deny access list, the connection is denied. If it is listed in the grant access list, the connection is allowed and processing continues.
Additional rules to check are listed here: