VPN ports Cheat Sheet

TCP/IP stands for Transm­ission Control Protocol and IP for Internet Protocol. These protocols are respon­sible for transp­orting and managing the data across the network. The IPv4 requires a 4 byte address to be assigned to each network interface card that exists on all the computers in the network where as the Ipv6 assigns a 6 byte address. IP Addresses works almost like a house address without which determ­ining where data packets go would be imposs­ible.

The part of the IP address that defines the network is the network ID, and the latter part of the IP address defining the host address is the host ID. By the way, if you need to find out the IP address of your device, you can do this by visiting http:/­/ip­-lo­cat­ion­s.org. It will display your current IP and location.

Using this port and addressing scheme, the networking system can pass data, addressing inform­ation, and type of service inform­ation through the hardware, from one computer to another.

The network port is usually number and standard network protocols like TCP, IP, UDP attaches a port number to the data it sends. A port number is to be assigned to each message according to the TCP layer requir­ements. This port (logical reference) number determines the type of service provided. This software network port (address in the form of a number) is assigned to a service for commun­icating between a program and another progra­m/c­omm­uni­cation system.

This naming system is logical and pertains to the services that carry on long term conver­sation. A list that specifies the port used by the server process is known as its contact port. A service contact port is defined to provide specific service to unknown callers. These software network ports also connect internal programs on the same computer. Numbers from 0 to 1023 are used to identify a network service on the internet (Internet Protocol).

Each IP packet contains a TCP or UDP header which directs applic­ations to the approp­riate applic­ation in the server. Reserved port numbers and unassigned numbers can be used by applic­ation programs.

The Internet Assigned Numbers Authority (IANA) registers ports 1024 to 49151 for the conven­ience of internet contin­uity. Port numbers from 49151 to 65535 are called dynamic ports and are private. You could look up IANA for more details on assigned port numbers. The most well-known port is 80, which identifies HTTP traffic for a Web server.

The Well Known Ports are assigned by the IANA and on most systems can only be used by system (or root) processes or by programs executed by privileged users. Port numbers are straight unsigned integer values which range up to a value of 65535. Below is a list of well known ports and their services.

20,21 FTP (File transfer)
22 SSH (Remote login secure)
25 SMTP (Internet mail)
53 DNS (Host naming)
80 HTTP (Web)
88 Kerberos (computer authen­tic­ation protocol)

110 POP3 (Client access)
119 NNTP (Usenet newsgr­oups)
123 NTP (Network time)
137-139 NetBIOS (DOS/W­indows naming)
143 IMAP (Client access)
161,162 SNMP (Network manage­ment)
163,164 CMIP (Network manage­ment)

443 HTTPS (Web secure)
514 Syslog (Event logging)
563 NNTPS (Usenet newsgroups secure)
993/tcp IMAP4 over SSL, Internet Message Access Protocol
995/tcp POP3 over SSL, Post Office Protocol
989,990 FTPS (File transfer secure)
1723 Virtual private network (VPN)