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

32 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.

    • No its Domain name system because DNS is a server only the work of DNS is to convert domain name to ip address and ip address to domain name. That means lets us try to understand it in a simple example EX-if you want to search this is a domain but computer does not able to understand the name system can only understand to ip address for share packet(packet: establish connection between two device) so that why DNS convert this name to a ip address (ip address is like a path just like your postal pin code) then our system able to show us the HP website. But if you already know the ip address of HP website you can put it in your browser it also show you the same result. Before DNS there was an another server called WINS it converts only NetBios to ip address, NetBios is difficult to understand because it has 16digit alpha numeric so for that DNS was invented. This is the full work of DNS it is a process/system to convert ip to domain and domain to ip so we can not not say Domain Name Server.

      • Well explained! DNS : The protocol that resolves website names into IP addresses e.g. is the domain name or the name of the website and it has to be converted to an IP address , which is Then this IP address will also be converted to binary digits (bits).
        All this process of converting the domain name to an IP address helps the computer to understand as we all know that computers only understands 0(s) and (1s).

  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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