Here is a list of common ports.

Port Protocol Description
21 tcp FTP
22 tcp ssh
23 tcp Telnet
25 tcp SMTP
53 tcp DNS
53 udp DNS
67 udp DHCP Server
68 udp DHCP Client
69 udp TFTP
80 tcp HTTP ( web server )
88 tcp Kerberos
88 udp Kerberos
110 tcp POP3
117 udp XDMCP
123 udp NTP
135 tcp RPC
143 tcp IMAP
161 tcp SNMP ( Simple Network Management Protocol )
161 udp SNMP ( Simple Network Management Protocol )
389 tcp LDAP
443 tcp HTTPS ( web server )
445 tcp SMB
465 tcp SMPTS ( Alt )
587 tcp SMPTS
631 tcp CUPS IPP Port
631 udp CUPS IPP Port
636 tcp LDAPS
993 tcp IMAPS
995 tcp POP3S
1433 tcp MS SQL
2049 tcp NFS
3128 tcp SQUID ( Proxy )
3306 tcp mysql
3389 tcp Microsoft Remote Desktop
5432 tcp PostgreSQL
5000 tcp Python Flask Application
5060 tcp SIP
5060 udp SIP
5061 tcp SIP ( encrypted )
5061 udp SIP ( encrypted )
5555 tcp Android Debug Bridge
5800 tcp VNC
5900 tcp VNC
6000-6005 tcp Xorg XDMCP (:0 - :5)
6665-6669 tcp IRC
6665-6669 udp IRC
8080 tcp HTTP ( Alt )
8181 tcp HTTPS ( Java Application Server )
8443 tcp HTTPS ( Alt )
8686 tcp Java JMX
9100 tcp Jet Direct / Print Port
32400 tcp PLEX Access Port