Common TCP Ports

The TCP/IP protocol assigns ports to standard software so it can send data to the correct process when it is all running on a single machine.

See the Useful Links section (below) for the complete list.

Common Ones I Use

Port Description
22 Secure Shell (SSH)
23 Telnet
25 SMTP
53 DNS
67 DHCP
68 DHCP
80 HTTP
110 POP3
123 Network Time Protocol (NTP)
143 IMAP
161 SNMP
366 SMTP
389 LDAP
443 HTTPS
465 SMTP SSL
631 Internet Printing Protocol (IPP)
993 IMAP4 SSL
995 POP3 SSL
1433 Microsoft SQLServer
3306 MySQL
5432 PostgreSQL
6379 Redis

Other I have looked up

Port Description
20 FTP - data
21 FTP - control
69 TFTP
79 finger
113 IDENT [Steve Gibson article on why you see it](https://grc.com/port_113.htm) - my install of ProFTPd did it until I specifically disabled it.
119 NNTP (NetNews)
135, 137, 139 Microsoft Networking
194 IRC
220 IMAP v3
445 Microsoft Directory Services
500 IKMP (used for some VPNs)
902 VMWare Management Console
1311 Dell OpenManage's Web Server
3389 Remote Desktop Protocol (RDP)
5500+ VNC server connecting to viewer
5800 VNC web interface
5900+ VNC viewer connecting to server

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