Warning
This is a fairly advanced tutorial in terms of theory and may require an understanding of how routing works in order to fully understand it. I will do my best to keep it as simple as possible.
Note
This tutorial applies to Windows Computers running Windows Vista, 7 or 8
In this tutorial I am going to be showing you how you can enable RIP listener on your computer as well as showing why you would want to use it and what benefits it can bring. Firstly, what is RIP? RIP stands for
Routing Information Protocol and is a legacy routing protocol that routers can use so that they know how to route traffic in a network. Typically its uses are confined to routers only as they are the ones used to route your traffic in a inter-network however your computer can leverage the information exchanged. Through doing so it allows your computer to dynamically choose which default gateway to use when reaching a remote network. Normally, if the destination network is not in the same subnet as the hosts it would send the traffic to the configured default gateway to route the traffic. With the use of RIP where there are multiple default gateways it allows your computer to appropriately choose which one to use when reaching a network.
To better demonstrate its uses I am going to be using the following topology for this tutorial.
Currently, the
Win7 device is using
R1 to reach any network outside of
10.1.1.0/24. For example, to reach
PCB the traffic is getting sent to
R1 and is then looped back and sent to
R2 who then routes it over to
PCB. We can verify this by performing a traceroute over to
PCB and establish the path that is being taken.
Note
Obviously this isn't the optimal path that could be taken as the
Win7 device could send the traffic straight to
R2. The issue is that you can only configure 1 default gateway on a client PC and therefore is not possible without performing some routing on our machine. To resolve this we could use static routes which manually tell this device that to reach
PCB go to
R2 however this would not scale well. Imagine if we had 20 computers attached. Manually configuring all of them for this may not be feasible. The next option would be to enable RIP listener so our host can leverage the routing information being made by
R2 and allow it to dynamically route the traffic.
Enable The Feature
The first step is to enable the feature so it can listen to the routing information being exchanged and then that is it! The hard part it really done on the routers itself. I will show the configuration made on the routers however I will not be going into too much depth on them as this focus is on end host routing.
1. The first step is to click on
Start and then going to
control panel.
2. Once in
control panel, click on the
programs section.
3. After that click on the sub option under
Programs and Features called
'Turn Windows Features on or off'.
4. If prompted by UAC (
User Account Control) then click on
Yes or
Continue.
5. Now scroll down until you see the '
RIP Listener' feature. Check the Tick-box next to it and then click on OK to enable the feature.
Once clicked it will take a few minutes to configure the feature.
6. The final step in completing the enabling process is to reboot the machine so the relevant services are enabled.
Verification
After that it should be completed! Now all you need to do is wait until the next routing update is sent from the router so your host can configure its routing table accordingly. To verify this we can use a couple of commands. For example, to view the routing table made we can input the following syntax into a command prompt:
From the above image we can see that this machine has chosen to use
10.1.1.2 (
R2) to reach the
172.16.0.0/16 network. Yet it has also been configured to use
R1 as the default gateway. To verify that this is actually what is happening we can perform another traceroute to
PCB to show that the path has changed. In addition to this I have also performed a traceroute to
PCA as well to verify that the default gateway is also being used.
Now that optimal routing is in place I would just like to show you briefly what is included in a RIP packet and how the computer knew it had to go to
R2. The Wireshark capture can be seen below:
In this routing update we can see that a network was advertised (
172.16.0.0) out via RIP and was sent from a source IP address of
10.1.1.2 (
R2). When the
Win7 device received this update it processed it and saw the advertised network. Then it installed the network into its routing table with a next hop as
R2 because
R2 was the one who sent the routing update. That's it!
To complete this tutorial please see attached below the configuration on
R2 to enable RIP as well as the capture footage should you wish to analyse it yourself. For more information on Wireshark please see -
https://www.sysnative.com/forums/ne...hark-protocol-analyser-sniffing-the-wire.html
Note
RIP Listener only supports RIPv1 therefore routing has to be of classful boundaries.
Hope This Helps,
Josh
