TCP/IP Configuration and Management Manual

TCP/IP Configuration and Management Manual—427132-004
C-1
C
Well-Known Port Numbers for TCP
and UDP
This appendix lists the port numbers preassigned to specific services when accessed
from TCP or UDP.
Table C-1
, Table C-2, and Table C-3 give the name or names of each service as used
in C programs. These port numbers are provided in the file
$SYSTEM.ZTCPIP.SERVICES.
Table C-1. Port Numbers for Network Services
Port Number Protocol C Name(s)of Service or Function
7 TCP,UDP echo
9 UDP discard, sink null
11 TCP systat
13 TCP daytime
15 TCP netstat
20 TCP ftp-data
21 TCP ftp
23 TCP telnet
25 TCP smtp, mail
37 TCP,UDP time, timserver
42 UDP name, nameserver
43 TCP whois, nicname (usually tosri-nic)
53 TCP,UDP domain
101 TCP hostnames, hostname (usually tosri-nic)
111 TCP,UDP sunrpc
Table C-2. Port Numbers for Host-Specific Functions
Port Number Protocol C Name(s) of Service or Function
69 UDP tftp
77 TCP rje
79 TCP finger
87 TCP link, ttylink
95 TCP supdup
105 TCP csnet-ns