How to Make a Router Table

Level of difficulty: Intermediate

Since the routing table is closely associated with the TCP/IP communication stack, it is advisable for computer systems running under the Microsoft Windows Operating System to initially execute the “IPCONFIG /all” command in the command shell window to have an idea about how the service is set up in the host machine. By checking this type of information, the computer user will have a better understanding on the role of the routing table which is usually used to find the best and shortest path any data packet can take to move from the host machine to the routing hardware device. Once it reaches the routing device, it is automatically sent out to its intended recipient using the underlying communication framework of the Internet. The route command allows the defining of the network, subnet mask, and the IP of the gateway.

Materials Needed:
- Router hardware
- command shell
- computer connected to a network
Step 1
To add an entry into the routing table of the computer system, the 'Route (-f) (-p) (command {destination})' syntax may be used. In this command line, the (-f) option clears all entries associated with the gateway. The (-p) option on the other hand creates a specific persistent route. The route is normally maintained despite a system reboot. This command line is generally used for the Microsoft Windows Operating System environment.
Step 2
Under the Linux or UNIX Operating System, the command shell prompt is also used to execute the routing table commands. In these systems, the $ netstat -r -n or the $ route -n instructions are used to display the contents and configuration of the routing table. In computer systems running under these platforms, the table is automatically generated depending on the current configuration of the TCP/IP communication stack.
Step 3
Additional commands for the Route command in the Windows platform include the Print, Delete, Change, and Add options. By issuing the Route Add command, the destination, gateway, and subnet mask should be specified. Additional elements are the inclusion of the interface and metric considered as optional components. An example of a minimal syntax would be 'Route Add'. By issuing this command, additional routes are incorporated into the earlier created router table.
Step 4
Once the router table has been created, any computer system running under the Linux, UNIX, or the Microsoft Windows Operating System platforms will be able to make effective routing decisions. The role of the router table is to control the decisions associated with the data exchange process. The configuration may also be reviewed using the IPCONFIG command at the shell prompt.