> For the complete documentation index, see [llms.txt](https://cybersec.th4ntis.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cybersec.th4ntis.com/networking/common-ports-and-protocols.md).

# Common Ports and Protocols

Common TCP Ports:

* 21 - FTP - File Transfer Protocol
* 22 - SSH - Secure Shell
* 23 - Telnet
* 25 - SMTP - Simple Mail Transfer Protocol
* 53 - DNS - Domain Name System
* 80 - HTTP - Hyper Text Transfer Protocol
* 443 - HTTPS - Hyper Text Transfer Protocol Secure
* 110 - POP3 - Post Office Protocol
* 139/445 - SMB - Secure Message Block / Samba
* 143 - IMAP - Internet Message Access Protocol
* 389 - LDAP - Lightweight Direcotry Access Protocol (Both TCP and UDP)
* 990 - FTPS - FTP over TLS/SSL
* 3306 - MySQL
* 3389 - RDP - Remote Desktop Protocol

Common UDP Ports: 

* 53 - DNS - Domain Name System
* 67/68 - DHCP - Dynamic Host Configuration Protocol
* 69 - TFTP - Trivial File Transfer Protocol
* 123 - NTP - Network Time Protocol
* 161 SNMP - Simple Network Management Protocol

\*Note:\* some ISPs(Comcast) block port 25(SMTP) for residential and some commercial by default so sometimes they will change it to Port 587.