TCP and UDP ports

FTP (File Transfer Protocol)

Uses port 21 for session control.

TCP

The most commonly used protocol on the Internet and any TCP/IP network. Whereas the IP protocol deals only with packets, This enables two hosts to establish a connection and exchange streams of data.

FTPS (File Transfer Protocol Secure)

An extension of FTP that uses SSL or TLS to encrypt FTP traffic. Some implementations of FTPS use ports 989 and 990.

SFTP (Secure File Transfer Protocol)

An extension of Secure Shell (SSH) using SSH to transmit the files in an encrypted format. transmits data using TCP port 22.

SCP (Secure Copy Protocol)

One of the first SSH-enabled programs to appear after the introduction of SSH, and was one of the first protocols used to transfer data securely between two hosts and thus might have replaced FTP. Runs on SSH TCP port 22

SSH (Secure Shell)

A network protocol for secure transfer of data between computers. Uses TCP port 22

DHCP (Dynamic Host Configuration Protocol)

A network service that provides automatic assignment of IP addresses and other TCP /IP configuration information. Uses UDP ports 67, 68

TCP (Transmission Control Protocol)

Provides reliable, ordered, and error-checked delivery of a stream of packets on the internet.

UDP (User Datagram Protocol)

Protocol that operates instead of TCP in applications where delivery speed is important and quality can be sacrificed.

DNS (Domain Name System)

The Internet's system for converting alphabetic names into numeric IP addresses. Uses TCP and UDP port 53.

HTTP (Hypertext Transfer Protocol)

The protocol used for transmitting web pages over the Internet. Used TCP port 80.

HTTPS (Hypertext Transfer Protocol Secure)

An encrypted version of HTTP. It uses TCP port 443.

IMAP (Internet Message Access Protocol)

A common protocol for retrieving email messages via the Internet. Used port 143.

IMAPS (Internet Message Access Protocol Secure)

An encrypted version of IMAP. It can be encrypted with SSL or TLS and uses port 993 by default.

ISAKMP (Internet Security Association and Key Management Protocol)

Defines procedures and packet formats to establish, negotiate, modify and delete Security Associations. Uses UDP port 500.

IKE (Internet Key Exchange)

A protocol used by IPSec to create a master key, which in turn is used to generate bulk encryption keys for encrypting data. Uses port 500.

Kereberos

The most commonly used authentication protocol. Uses port 88.

L2TP (Layer 2 Tunneling Protocol)

An extension of Point-to-Point Tunneling Protocol used by an Internet Service Provider to enable the operation of a Virtual Private Network. UDP port 1701.

LDAP (Lightweight Directory Access Protocol)

A communications protocol that defines how a client can access information, perform operations, and share directory data on a server. Uses TCP/UDP port 389.

LDAPS (Lightweight Directory Access Protocol Secure)

A secure form of LDAP. Uses port 636

NNTP (Network News Transfer Protocol)

A protocol used to post and retrieve messages from newsgroups, usually from the worldwide bulletin board system called USENET. Uses port 119.

NTP (Network Time Protocol)

An Internet protocol that enables synchronization of computer clock times in a network of computers by exchanging time signals. Uses port 123.

POP3 (Post Office Protocol version 3)

A protocol used from retrieving email from a mailbox on the mail server. Uses port 110.

POP3S (Post Office Protocol version 3 Secure)

An encrypted version of POP3. It can be encrypted with SSL or TLS and uses port 995 by default.

PPTP (Point-to-Point Tunneling Protocol)

A more common VPN (virtual private network) but is a less secure option. Uses TCP port 1723.

L2F (Layer 2 Forwarding)

A tunneling protocol developed by Cisco Systems to support the creation of VPNs.

RADIUS (Remote Authentication Dial-In User Service)

A networking protocol, operating on port 1812 and 1813 that provides centralized Authentication, Authorization, and Accounting (AAA or Triple A) management for users who connect and use a network service.

RDP (Remote Desktop Protocol)

The protocol used by Microsoft's Terminal Services to remotely connect to another Windows System. Used port 3389.

SSH, SFTP, SCP, rsync

Unblocking port number 22 enables what type of traffic?

SIP (Session Initiation Protocol)

A set of Application layer signaling and control protocols for multiservice, packet-based networks, and is used to make an initial connection between hosts for transferring multimedia data on ports 5060 and 5061.

SMTP (Simple Mail Transfer Protocol)

The default port used for sending emails between servers. Uses TCP port 25

SMTPS (Simple Mail Transfer Protocol Secure)

An encrypted version of SMTP. It can be encrypted with TLS or SSL and uses port 465 by default.

SNMP (Simple Network Management Protocol)

An Application-layer protocol used to exchange information between network devices. Uses UDP port 162.

SNMP (Simple Network Management Protocol)

protocol specifically designed for managing devices on IP networks. Receives requests from UDP port 161

Syslog

Uses UDP port 514 and TCP port 6514 to send event notification messages across IP networks to event message collectors

TACACS (Terminal Access Controller Access Control System)

A CISCO authentication protocol common to UNIX networks that allows a remote access server to forward a user's logon password to an authentication server to determine whether access can be allowed to a given system. Uses port 49.

Telnet

A protocol used to remotely connect to other services via plaintext., and allows the user to test individual ports and see whether they are open or not. Uses port 23

IPSec (Internet Protocol Security)

protocol within the TCP/IP suite that encrypts and authenticates IP packets. UDP port 500 + ip protocol 50 and 51