List of Common Network Port Numbers

Objectives: Learn common port numbers and services, and which transport protocol they use.

Prerequisites: you have to know about TCP/IP protocols in general.

Key terms: port numbers, network, common, protocol, services

Network ports are provided by the TCP or UDP protocols at the Transport layer. They are used by protocols in the upper layers of the OSI model. Port numbers are used to determine what protocol incoming traffic should be directed to. Ports allow a single host with a single IP address to run network services. Each port number identifies a distinct service, and each host can have 65535 ports per IP address. Port use is regulated by the Internet Corporation for Assigning Names and Numbers (ICANN). By ICANN there are three categories for ports:

  • From 0 to 1023 – well known ports assigned to common protocols and services
  • From 1024 to 49151 – registered ports assigned by ICANN to a specific service
  • From 49152 to 65 535 – dynamic (private, high) ports range from 49,152 to 65,535. Can be used by any service on an ad hoc basis. Ports are assigned when a session is established, and released when the session ends.

Well known ones are:

Port Service name Transport protocol
 20, 21  File Transfer Protocol (FTP)  TCP
 22  Secure Shell (SSH)  TCP and UDP
 23  Telnet  TCP
 25  Simple Mail Transfer Protocol (SMTP)  TCP
 50, 51  IPSec  
 53  Domain Name System (DNS)  TCP and UDP
 67, 68  Dynamic Host Configuration Protocol (DHCP)  UDP
 69  Trivial File Transfer Protocol (TFTP)  UDP
 80  HyperText Transfer Protocol (HTTP)  TCP
 110  Post Office Protocol (POP3)  TCP
 119  Network News Transport Protocol (NNTP)  TCP
 123  Network Time Protocol (NTP)  UDP
 135-139  NetBIOS  TCP and UDP
 143  Internet Message Access Protocol (IMAP4)  TCP and UDP
 161, 162  Simple Network Management Protocol (SNMP)  TCP and UDP
 389  Lightweight Directory Access Protocol  TCP and UDP
 443  HTTP with Secure Sockets Layer (SSL)  TCP and UDP
 989, 990  FTP over SSL/TLS (implicit mode)  TCP
 3389  Remote Desktop Protocol  TCP and UDP

29 thoughts on “List of Common Network Port Numbers”

    • No, it’s not. The “S” in “DNS” stands for “System” as DNS can also be a protocol.
      It could also be a query, which is a Domain Naming System query. DNS does not necessary reference a server when we talk about the protocol — Domain Name System queries reach out and query a Domain Name System server hence “DNS Server”.
      The “Server” aspect of DNS is only a small subset of what DNS is, so calling it by its less generic name could be misleading.

  1. only domain name system. and its a type of server so its not domain name server… plz correct this

  2. Port 135 is reserved for RPC (Remote Protocol Call)/DCOM using both TCP and UDP,
    Only ports 137, 138 and 139 are reserved for NETBIOS

  3. 50, 51 IPSec port it’s wrong>>>> 50 and 51 are the layer 4 protocols AH and ESP ipsec would normaly use udp 500 or 4500 as ports

    • The key difference between Telnet and SSH is that SSH uses encryption, which means that all data transmitted over a network is secure from eavesdropping.


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