Useful ports and port numbers

There are 65,535 UDP and the same number of TCP ports out of which the first 1024 are known as well known ports or ports that are used for important functions like http, ftp etc. It is good to know some of the port numbers as it might come handy.

20    FTP(data transfer)
21   FTP (control)
22   SSH
23   Telnet
25   SMTP
53   DNS
80   HTTP
88   Kerberos
110 POP3
115 SFTP
137-139 NETBIOS
143 IMAP
156 SQL
161 SNMP
179 BGP
443 HTTPS