Dňa 26. augusta 2026 18:35:09 UTC používateľ Ralph Seichter via mailop <[email protected]> napísal: >* Randolf Richardson, Postmaster via mailop:
>More importantly though, like I wrote before: No outbound SMTP mail >connection is supposed to ever be established to third parties. That is >being enforced via "relayhost = [172.16.x.y]:587" (Postfix). Private >destination address, and destination port != 25. The Postfix instance >also does NOT listen on anything except localhost, i.e. accepts no >inbound connections. Even if someone managed to breach the firewall. >That's not a machine one expects to end up on a blocklist, IMO. One do not need SMTP server to send mails, any tool capable to send text over network can be mail client, even BASH itself. I would to start, for now, by adding firewall rule to log/block outbond connections to TCP port 25. But if your machine is already compromised it can be not enough to do it on that host... regards regards -- Slavko https://www.slavino.sk/ _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
