TCP 21 File Transfer [Control]
TCP 22 SSH Remote Login Protocol
TCP 23 Telnet
TCP 24 any private mail system
TCP 25 Simple Mail Transfer
TCP 26 Unassigned
TCP 27 NSW User System FE
TCP 28 Unassigned
TCP 29 MSG ICP
TCP 30 Unassigned
TCP 31 MSG Authentication
TCP 32 Unassigned
TCP 33 Display Support Protocol
TCP 34 Unassigned
TCP 35 any private printer server
TCP 36 Unassigned
TCP 37 Time / W32.Sober.I virus
TCP 38 Route Access Protocol
TCP 39 Resource Location Protocol
TCP 40 Unassigned