D-1
Cisco Secure Router 520 Series Software Configuration Guide
OL-14210-01
APPENDIX
D

Common Port Assignments

Table D-1 lists currently assigned Transmission Control Protocol (TCP) port numbers. To the extent
possible, the User Datagram Protocol (UDP) uses the same numbers.
Tab l e D-1 TCP Port Numbers
Port Keyword Description
0 — Reserved
1–4 —Unassigned
5RJE Remote job entry
7ECHO Echo
9DISCARD Discard
11 USERS Active users
13 DAYTIME Daytime
15 NETSTAT Who is up or NETSTAT
17 QUOTE Quote of the day
19 CHARGEN Character generator
20 FTP-DATA File Transfer Protocol (data)
21 FTP File Transfer Protocol
23 TELNET Terminal connection
25 SMTP Simple Mail Transport Protocol
37 TIME Time
39 RLP Resource Location Protocol
42 NAMESERVER Hostname server
43 NICNAME Who is
49 LOGIN Login Host Protocol
53 DOMAIN Domain name server
67 BOOTPS Bootstrap Protocol Server
68 BOOTPC Bootstrap Protocol Client
69 TFTP Trivial File Transfer Protocol