One key aspect of network and security engineer is to have a good understanding of well-known services and their port numbers (TCP and UDP).
Well Known Port Numbers Information
Below is a list of commonly used well-known protocols and their port number. Additionally, RFC reference will help to have more detail on the enlisted transport-layer common port numbers –
Related- TCP vs UDP
| PORT NUMBER | TRANSPORT PROTOCOL | SERVICE NAME | RFC |
|---|---|---|---|
| 20, 21 | TCP | File Transfer Protocol (FTP) | RFC 959 |
| 22 | TCP and UDP | Secure Shell (SSH) | RFC 4250-4256 |
| 23 | TCP | Telnet | RFC 854 |
| 25 | TCP | Simple Mail Transfer Protocol (SMTP) | RFC 5321 |
| 53 | TCP and UDP | Domain Name Server (DNS) | RFC 1034-1035 |
| 67, 68 | UDP | Dynamic Host Configuration Protocol (DHCP) | RFC 2131 |
| 69 | UDP | Trivial File Transfer Protocol (TFTP) | RFC 1350 |
| 80 | TCP | HyperText Transfer Protocol (HTTP) | RFC 2616 |
| 110 | TCP | Post Office Protocol (POP3) | RFC 1939 |
| 119 | TCP | Network News Transport Protocol (NNTP) | RFC 8977 |
| 123 | UDP | Network Time Protocol (NTP) | RFC 5905 |
| 135-139 | TCP and UDP | NetBIOS | RFC 1001-1002 |
| 143 | TCP and UDP | Internet Message Access Protocol (IMAP4) | RFC 3501 |
| 161, 162 | TCP and UDP | Simple Network Management Protocol (SNMP) | RFC 1901-1908, 3411-3418 |
| 179 | TCP | Border Gateway Protocol (BGP) | RFC 4271 |
| 389 | TCP and UDP | Lightweight Directory Access Protocol | RFC 4510 |
| 443 | TCP and UDP | HTTP with Secure Sockets Layer (SSL) | RFC 2818 |
| 500 | UDP | Internet Security Association and Key Management Protocol (ISAKMP) / Internet Key Exchange (IKE) | RFC 2408 – 2409 |
| 636 | TCP and UDP | Lightweight Directory Access Protocol over TLS/SSL (LDAPS | RFC 4513 |
| 989/990 | TCP | FTP over TLS/SSL | RFC 4217 |
Download the table here.
Continue Reading:
Difference between IP Address and Port Number
ABOUT THE AUTHOR
I am here to share my knowledge and experience in the field of networking with the goal being – “The more you share, the more you learn.”
I am a biotechnologist by qualification and a Network Enthusiast by interest. I developed interest in networking being in the company of a passionate Network Professional, my husband.
I am a strong believer of the fact that “learning is a constant process of discovering yourself.”
– Rashmi Bhardwaj (Author/Editor)
