| Pport Numbers | The Network Administrator |
Port numbers are from 0 to 65536. Ports 0 to 1024 are reserved for use by certain privileged services. For the HTTP service, port 80 is defined as a default and it does not have to be specified in the Uniform Resource Locator (URL). Port Numbers are typically found in the services file on your system. List below is an example.
# This file contains port numbers for well-known services as defined by
# RFC 1060 (Assigned Numbers).
#
# Format:
#
# <service name> <port number>/<protocol> [aliases...]
[#<comment>]
| echo | 7/tcp |
| echo | 7 /udp |
| discard | 9/tcp sink null |
| discard | 9/udp sink null |
| systat | 11/tcp |
| systat | 11/tcp users |
| daytime | 13/tcp |
| daytime | 13/udp |
| netstat | 15/tcp |
| qotd | 17/tcp quote |
| qotd | 17/udp quote |
| chargen | 19/tcp ttytst source |
| chargen | 19/udp ttytst source |
| ftp-data | 20/tcp |
| ftp | 21/tcp |
| telnet | 23/tcp |
| smtp | 25/tcp mail |
| time | 37/tcp timserver |
| time | 37/udp timserver |
| rlp | 39/udp resource # resource location |
| name | 42/tcp nameserver |
| name | 42/udp nameserver |
| whois | 43/tcp nicname # usually to sri-nic |
| domain | 53/tcp nameserver # name-domain server |
| domain | 53/udp nameserver |
| nameserver | 53/tcp domain # name-domain server |
| nameserver | 53/udp domain |
| mtp | 57/tcp # deprecated |
| bootp | 67/udp # boot program server |
| tftp | 69/udp |
| rje | 77/tcp netrjs |
| finger | 79/tcp |
| link | 87/tcp ttylink |
| supdup | 95/tcp |
| hostnames | 101/tcp hostname # usually from sri-nic |
| iso-tsap | 102/tcp |
| dictionary | 103/tcp webster |
| x400 | 103/tcp # ISO Mail |
| x400-snd | 104/tcp |
| csnet-ns | 105/tcp |
| pop | 109/tcp postoffice |
| pop2 | 109/tcp # Post Office |
| pop3 | 110/tcp postoffice |
| portmap | 111/tcp |
| portmap | 111/udp |
| ... ... |