Welcome to Bucaro TecHelp!

Bucaro TecHelp
Maintain Your Computer and Use it More Effectively
to Design a Web Site and Make Money on the Web

About Bucaro TecHelp About BTH User Agreement User Agreement Privacy Policy Privacy Site Map Site Map Contact Bucaro TecHelp Contact RSS News Feeds News Feeds

Each year 1.5 million shelter animals are euthanized (670,000 dogs and 860,000 cats). Source: ASPCA. The solution is not to shelter unwanted pets, but to SHUT DOWN THE PET MILLS. Anyone who wants a pet will just have to adapt a great pet from a shelter.

Network Address Translation (NAT) Protocol

NAT is a protocol that is used by a router to convert IP addresses on the internal private network to the it's own public IP address for the Internet. If NAT were not used each computer on the internal private network would be visible to the Internet. Also, Internet IP addresses are limited. NAT allows IP addresses to be assigned on the internal network regardless of whether they have been allocated on the Internet.

Network Address Translation

Here are the steps taken by NAT

1. A computer on the internal network makes a request, through the router, for a resource located on the Internet.

2. The router records the computer's IP address as an entry in its NAT table.

3. The router changes the private IP address in the packet to the routers public IP address. It records the new address in the NAT table entry.

4. The router sends the resource request to the destination address on the Internet.

5. The host at the Internet address returns the requested resource to the routers public IP address.

6. The router looks in it's NAT table for the related private IP address and sends the resource to the computer on the internal network.

Sometimes NAT is referred to as PAT for Port Address Translation. This is because as stated earlier, Internet IP addresses are limited. Usually a router has only one public IP address. So for each request for a resource located on the Internet, in its NAT table, it actually records the internal computer's IP address and a unique PORT number for the routers public IP address.

The host at the Internet address returns the requested resource to the routers public IP address⁄port number. The router then looks in its NAT table for the internal network IP address related to that port number.

Actually almost all IP addresses on the Internet are address⁄port combinations. Knowing the destination IP address may get the packets to the correct destination host, but it needs the port number to get to the correct destination service.

More Network Troubleshooting and Support Articles:
• Troubleshooting the Intermediate System to Intermediate System (IS-IS) Protocol
• Fiber Optic Cable Tester - What Is It and How to Use?
• How to Use a Network Cable Toner
• Turning Names (URLs) Into IP Addresses
• Why Bother to Design Your SME Network?
• How Snort's Stealth TCP Port Scanning Works
• Network Address Translation (NAT) Protocol
• Network Log Collection and Monitoring
• Building the Backbone Network
• Network Management Components - The Basics of an Effective Management Strategy

RSS Feed RSS Feed

Follow Stephen Bucaro Follow @Stephen Bucaro

Computer Networking Sections

Fire HD
[Site User Agreement] [Privacy Policy] [Site map] [Search This Site] [Contact Form]
Copyright©2001-2018 Bucaro TecHelp 13771 N Fountain Hills Blvd Suite 114-248 Fountain Hills, AZ 85268