Billion Electric Company 7300M User Manual

In TCP/IP and UDP networks a port is a 16-bit number used to identify which application 

program (usually a server) incoming connections should be delivered to. Some ports have 

numbers that are pre-assigned to them by the IANA (the Internet Assigned Numbers 

Authority), and these are referred to as “well-known ports”. Servers follow the well-known 

port assignments so clients can locate them. 

If you wish to run a server on your network that can be accessed from the WAN (i.e. from 

other machines on the Internet that are outside your local network), or any application that 

can accept incoming connections (e.g. Peer-to-peer/P2P software such as instant 

messaging applications and P2P file-sharing applications) and are using NAT (Network 

Address Translation), then you need to configure your router to forward these incoming 

connection attempts using specific ports to the PC on your network running the application. 

You also need to use port forwarding if you wish to host an online game server. 

The reason is that when using NAT, your publicly accessible IP address is used by and 

points to your router, which needs to deliver all traffic to the private IP addresses used by 

your PCs. Please see the WAN configuration section of this manual for information on NAT. 

The Internet Assigned Numbers Authority (IANA) is the central coordinator for the 

assignment of unique parameter values for Internet protocols. Port numbers range from 0 to 

65535, but only port numbers 0 to 1023 are reserved for privileged services and are 

designated as “well-known ports”. The registered ports are numbered from 1024 through 

49151. The remaining ports, referred to as dynamic ports, or private ports, are numbered 

from 49152 through 65535. 

Examples of well-known and registered port numbers are shown below, for further 

information, please see IANA’s website at: 

For help on determining which private port numbers are used by common applications on 

this list, please see the FAQs (Frequently Asked Questions) at: 

http://www.billion.com