Networking

* What Is a Port Number?

In computer networking, a port number is part of the addressing information used to identify the senders and receivers of messages. Port numbers are most commonly used with TCP/IP connections. Home network routers and computer software work with ports and sometimes allow you to configure port number settings. These port numbers allow different applications on the same computer to share network resources simultaneously.  

*Definition: URL  

URL stands for Uniform Resource Locator. A URL is a formatted text string used by Web browsers, email clients and other software to identify a network resource on the Internet. Network resources are files that can be plain Web pages, other text documents, graphics, or programs. URL strings consist of three parts (substrings):

1. Network protocol 2. Host name or address 3. File or resource location 

*Physical network ports & Virtual ports

In computer networking, the term port can refer to either physical or virtual connection points.Physical network ports allow connecting cables to computers, routers, modems and other peripheral devices. Several different types of physical ports available on computer network hardware include:   

Ethernet ports, USB ports, serial ports

Virtual ports are part of TCP/IP networking. These ports allow software applications to share hardware resources without interfering with each other. Computers and routers automatically manage network traffic traveling via their virtual ports. Network firewalls additionally provide some control over the flow of traffic on each virtual port for security purposes

*Port Number

SERVICE	PROTOCOL	PORT NO:
FTP	TCP	20 - 021
Telnet	TCP	23
SMTP	TCP	25
DNS	TCP/UDP	53
HTTP	TCP	40
POP3	TCP	110
GOFOR	TCP	70
SNMP	UDP	161
RIP	UDP	520

  

*Top Lebel Domain:

.com	Commercial
.gov	Governmental
.mil	Military
.edu	Education
.net	Network Service
.org	Origination
.int	International