IP routing: What is it and how it works

What is IP routing?

When data packets are transferred to different routers, the routers rely on a routing table to know exactly where to send the packet on to. Once the packet has been received by the next router, it follows the same process until the data arrives at the desired final destination.

Each router has its own forwarding table, with designated destinations based on the IP address of the final router and the IP data packet header. The IP address contained in the data packet is typically enough information to hop between the necessary routers. When the data packets hop between different types of routers and networks, several types of routing protocols will need to be used.

Default gateway

If the router’s forwarding table can’t find the IP address for the next network, then the data packets are forwarded on through the default gateway. A default gateway acts like a communication node that can interact with other remote networks, even those that rely on different networking tech. The default gateway will typically have a route to the desired destination.

Routing table

The routing table for each internet router contains all the information necessary to send data packets on to the correct destination. The information stored consists of:

• A network destination with the necessary subnet mask designation to help specify the exact range of IP addresses the data needs to be sent to.
• The IP address of the next destination router.
• An interface for the data packet to exit and hop to the next router.

What does IP route 0.0 0.0 mean?

The 0.0 0.0 designation has multiple meanings, but in the context of IP routing, 0.0 0.0 refers to when a data packet does not specify the destination subnet it needs to be forwarded to. It generally means that the data packet doesn’t have any more different remote routers to hop across. The packet is finally directly connected to the destination network.

Types of routing protocols

While the TCP/IP network protocol is a standard, different networks don’t all use the same routing protocols. Here’s the list of protocols that are used to help direct data packets to the correct router.

• IP. The Internet Protocol provides the original destination of the packet, and the desired destination.
• RIP. The Routing Information Protocol is used for LAN and WAN. It comes in two versions, RIPv1 and RIPv2. RIPv2 was created in response to the inefficiencies of the original version.
• IS-IS. The Intermediate System to Intermediate System is used to relay internal routing information for a single system.
• BGP. The Border Gateway Protocol is used to relay routing information between multiple different systems.
• EIGRP. The Enhanced Interior Gateway Routing Protocol acts as a more efficient protocol for relaying router information than BGP or normal IGRP.
• OSPF. The Open Shortest Path First protocol gathers all router information in a single system and creates a network topology map. The map is shown as a routing table with different destination IP addresses.

Important IP route commands

IP route commands are important for figuring out a static route for a desired destination network. To find out the static route, the command requires a set of necessary identifying data first. The destination address, the IP address of the router needed to hop across (or the name of the interface connected with the destination) and any other control options.

An IP route command requires two syntaxes. The first is to specify the local interface and the location of the destination network. The second syntax is to specify the IP address of the next router that’s about to be hopped across. By identifying the address of the router needed to hop across, the router assumes the desired final destination is available on the next hop-router. This process continues until the final destination router is reached.

For specifying the local interface, try using this syntax:

Router(config)# ip route destination_network_# [subnet_mask]

interface_to_exit

[administrative_distance] [permanent]

For specifying the address for the next router to hop along, try using this syntax:

Router(config)# ip route destination_network_# [subnet_mask]

ip_address_of_next_hop_neighbor

[administrative_distance] [permanent]

IP Routing for Mesh Networks

Mesh network is LAN topology where all infrastructure nodes are directly connected to each other. The purpose of this interconnectivity is to efficiently transfer and move data around a network.

NordVPN’s Meshnet is a handy tool that provides all mesh network functions: traffic routing, remote access, and file sharing. Moreover, it lets you link up to 60 devices worldwide.

Easy-to-use Meshnet allows you access remote devices through encrypted tunnels, and it can also reroute online traffic through another machine. Essentially, you can take advantage of the online capabilities of a specific device from an IP address of your choice. For example, you can use your phone to reroute data from a home laptop or computer. Now, you’ll be able to access your internet from abroad, as if you were still at home.