New College Durham

Having an email server requires opening up firewalls on the DMZ on ports 25 TCP, 53 UDP DNS. The book Hacking for Dummies explains that these are among the most commonly hacked ports. TCP port 22 – SSH (secure shell) TCP port 23 – Telnet . TCP port 25 – SMTP (Simple Mail Transfer Protocol) TCP and UDP port 53 – DNS ................
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