TCP 0 Reserved
TCP 1 Port Service Multiplexer
TCP 2 Management Utility
TCP 3 Compression Process
TCP 4 Unassigned
TCP 5 Remote Job Entry
TCP 6 Unassigned
TCP 7 Echo
TCP 8 Unassigned
TCP 9 Discard
TCP 10 Unassigned
TCP 11 Active Users
TCP 12 Unassigned
TCP 13 Daytime (RFC 867)
TCP 14 Unassigned
TCP 15 Unassigned [was netstat]
TCP 16 Unassigned
TCP 17 Quote of the Day
TCP 18 Message Send Protocol
TCP 19 Character Generator
TCP 20 File Transfer [Default Data]