Common Ports

20 =   FTP data (File Transfer Protocol) 

21 =   FTP (File Transfer Protocol) 

22 =  SSH (Secure Shell) 

23 =   Telnet 

25 =   SMTP (Send Mail Transfer Protocol) 

43 =   whois 

53 =   DNS (Domain Name Service) 

68 =   DHCP (Dynamic Host Control Protocol) 

79 =   Finger 

80 =   HTTP (HyperText Transfer Protocol) 

110 =  POP3 (Post Office Protocol, version 3) 

115 =  SFTP (Secure File Transfer Protocol) 

119 =  NNTP (Network New Transfer Protocol) 

123 =  NTP (Network Time Protocol) 

137 =  NetBIOS-ns 

138 =  NetBIOS-dgm 

139 =  NetBIOS 

143 =  IMAP (Internet Message Access Protocol) 

161 =  SNMP (Simple Network Management Protocol) 

194 =  IRC (Internet Relay Chat) 

220 =  IMAP3 (Internet Message Access Protocol 3) 

389 =  LDAP (Lightweight Directory Access Protocol) 

443 =  SSL (Secure Socket Layer) 

445 =  SMB (NetBIOS over TCP) 

666 =  Doom 

993 =  SIMAP (Secure Internet Message Access Protocol) 

995 =  SPOP (Secure Post Office Protocol)

Ports between 1024 and 29151 are known as the Registered Ports. 

Basically, programs are supposed to register their use of these ports and thereby try to be careful and avoid stomping on each other. Here are some common ports and their programs.

1243 =  SubSeven (Trojan - security risk!) 


1352 =  Lotus Notes 


1433 =  Microsoft SQL Server 


1494 =  Citrix ICA Protocol 


1521 =  Oracle SQL 


1604 =  Citrix ICA / Microsoft Terminal Server 


2049 =  NFS (Network File System) 

3306 =  mySQL 

4000 =  ICQ 


5010 =  Yahoo! Messenger 


5190 =  AOL Instant Messenger 


5632 =  PCAnywhere 


5800 =  VNC 


5900 =  VNC 


6000 =  X Windowing System 


6699 =  Napster 


6776 =  SubSeven (Trojan - security risk!) 


7070 =  RealServer / QuickTime 


7778 =  Unreal 


8080 =  HTTP 


26000 =  Quake 


27010 =  Half-Life 


27960 =  Quake III 


31337 =  BackOrifice (Trojan - security risk!)