The Symantec Brightmail Gateway and Symantec Messaging Gateway uses Passive (PASV) FTP. Most firewall have the option for PASV.
Understanding PASV (Passive) FTP
The Symantec Brightmail Gateway and Symantec Messaging Gateway uses PASV FTP to perform the db-backup command and the Control Center’s backup section. Commonly, Firewall Administrators request strict port control and allow only few well-known protocol ports open. PASV FTP uses ephemeral port number (random temporary port number) along with port 21 to synchronize the FTP command responses.
Enable PASV option on the firewall.
Use SCP option with db-backup command within the CLI.
As an alternative, the Command Line Interface command db-backup provides SCP (secure copy) protocol. SCP uses a strict port assignment. The default port is port number 22 and provides secure upload to the data server.
Log in as Admin Perform the follow example db-backup command: > db-backup --file scp://email@example.com/storage