Routing Overview

IP routing at its most basic level allows a network packet to travel from its source address to its destination address. In a basic LAN there is normally only one network and traffic can be sent directly to the machine it is intended for. In larger, more complicated networks there are often multiple subnets which are separated by routers. The process of routing allows a network packet to reach its destination by examining a routing table.

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The biggest network of all, the Internet, is bound together by routers, e.g. Your e-mail may pass through several routers before reaching its destination. A router contains a list of the networks it is able to reach. Remote network packets are forwarded to routers which will pass the packet onto the correct destination (or another router).

Routing is the method computers use to transmit data packets from a machine on one subnet to a machine on a different subnet. This is done via a router:

Each computer is on a different network……but all computers can talk to each other through the router!

A computer with an IP address of and a computer with an IP address of would be on different networks.

A ping from the host to the host would not reach its target.

To access the distant machine a router must be enabled and configured with the correct entries.

Routing between networks can be achieved by using a combination of the following Hardware and Software solutions:

Solution 1: A multi-homed Windows Server (one with more than one network card) can function as a router.

Each NIC must be bound to the IP address of the network it is attached to. The Routing and remote Access service must be enabled on the server.

In TCP/IP Networking, the Default Gateway is the router which connects a network segment to other segments & possibly the rest of the world!

Solution 2: A dedicated, hardware Router. The router has several interfaces which can be used to link it up to different networks.

The router would normally be configured through a web browser or by using telnet.

Solution 3: Software Routing. There are two types: manually entered static routes and dynamic routing protocols, such as RIP. Routing works by using a routing table. A routing table is a database that stores route information. A route table is very similar to a road map. The route print command can be used to view a computer’s routing table.