system
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I don’t understand why I would need to have port 723 open on my firewall.
At the moment, I have port 25 open on my firewall. The firewall forwards port 25 traffic to a server on the internal lan where qmail is listening on port 25. After blacklist checking, that qmail “gateway” relays mail to port 725 (avastrelay) and virus free mail is relayed to port 825 (another qmail that handles mailbox delivery).