Commonly Used Ports
- 21 FTP File Transfer Protocol
- 22 SSH Secure Shell
- 23 Telnet Terminal Network
- 25 SMTP Simple Mail Transfer Protocol
- 53 DNS Domain Name System
- 80 HTTP Hypertext Transfer Protocol
- 88 Kerberos Kerberos
- 110 POP3 Post Office Protocol Version 3
- 119 NNTP Network News Transfer Protocol
- 137–139 NetBIOS NetBIOS Name, Datagram, and Session Services, respectively
- 143 IMAP Internet Access Message Protocol
- 161 SNMP Simple Network Management Protocol
- 389 LDAP Lightweight Directory Access Protocol
- 443 HTTPS Hypertext Transfer Protocol Secure (uses TLS or SSL)
- 445 SMB Server Message Block
- 1701 L2TP Layer 2 Tunneling Protocol
- 1723 PPTP Point-to-Point Tunneling Protocol
- 3389 RDP Remote Desktop Protocol (Microsoft Terminal Server)
Network Glossary
- DHCP: Short for Dynamic Host Configuration Protocol. It allows properly configured client computers to obtain IP addresses automatically from a DHCP server.
- Terminal Services:A type of thin-client terminal server computing. It allows client computers to connect to and take control of a server. Thin-client computers and PCs can connect to servers running Terminal Services.
- IPsec: A protocol within the TCP/IP suite that encrypts and authenticates IP packets. It is designed to secure any application traffic because it resides on the network layer.
- DNS:
A worldwide service that resolves host names to IP addresses. This facilitates proper communication between computers. A hierarchy of DNS servers communicates with each other in an effort to teach one another their name resolutions.