Cyber Security

Common ports and protocols

Here are a list of common ports and protocols you will see when scanning networks.

inkyvoxel

Feb 6, 2022 • 2 min read

When you are scanning networks, there are some common ports and protocols that you will see again and again. Here is a list of common TCP and UDP ports, with short descriptions of what each one is used for.

TCP

Common TCP ports:

Port 21 is FTP - File Transfer Protocol (FTP) is used to transfer files to and from a remote location.
Port 22 is SSH - Secure Shell (SSH) allows you to send remote commands to a server. Traffic over SSH is encrypted.
Port 23 is Telnet - Telnet allows you to send remote commands to the server. Traffic over telnet is not encrypted.
Port 25 is SMTP - Simple Mail Transfer Protocol (SMTP) is an e-mail protocol.
Port 53 is DNS - Domain Name Server (DNS) is used to resolve domain names to IP addresses.
Port 80 is HTTP - Hypertext Transfer Protocol (HTTP) is an insecure and unencrypted protocol used for communicating between a client and a server. It is commonly used for web servers.
Port 110 is POP3 - Post Office Protocol version 3 (POP3) is an e-mail protocol.
Port 139 is SMB - Samba (SMB) is a file share protocol. This port is typically used on older versions of Windows.
Port 143 is IMAP - Internet Message Access Protocol (IMAP) is an e-mail protocol.
Port 443 is HTTPS - Hypertext Transfer Protocol Secure (HTTPS) is the secure and encrypted version of HTTP, a protocol used for communicating between a client and a server. It is commonly used for web servers.
Port 445 is SMB - Samba (SMB) is a file share protocol. This port is typically used on newer versions of Windows.

UDP

Common UDP ports:

Port 53 is DNS - Domain Name Server (DNS) is used to resolve domain names to IP addresses.
Port 67 and 68 are DHCP - Dynamic Host Configuration Protocol (DHCP) is used for managing IP addresses within a network.
Port 69 is TFTP - Trivial File Transfer Protocol (TFTP) is similar to FTP, but uses UDP instead of TCP.
Port 161 is SNMP - Single Network Management Protocol (SNMP) provides a framework for asking devices about their performance and configuration over the network. The protocol is used by many different network management tools.