Linksys WRT54G uses 192.168.1.1

Name: JR Simpson

Why is it that my Linksys routers all use 192.168.1.1 as their default address? I had a Motorola WR850G router before this and it used 192.168.10.1. What is so special about the 192.168 prefix? Why doesn’t my router use my internet IP address?

The reason that your Linksys WRT54G uses the 192.168.x.x address range is simple: It’s reserved. Based on RFC1918 Address Allocation for Private Internets the 192.168 subnet has been reserved for private use. Most routers by default will ignore requests to the following IP blocks from the WAN (Internet) side:

10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255

The main benefit of the reserved address space is that it eliminates address conflicts between private networks. I, you, and your pet monkey can all be running the same IP address, say 192.168.1.50 on our computers and so long as we’re not connected to the same private network there won’t be a conflict.

The reason that we can both use the same IP address for each of our computers is because your router, well, ‘routes’ the information. Any request that you send to the internet goes through NAT (Network Address Translation). Basically, you send the request to your router, and the router sends the request to the internet for you. Once it gets a response from the internet the router then sends that response to the requesting machine.

This is why multiple computers all can use the router at once. Computer A requests Amazon.com and computer B requests Google. The router knows that it was computer A that requested Amazon, and so when Amazon’s servers respond to said request then the information is sent to the appropriate computer. That is, of course, a gross oversimplification of the process, but it explains the general concept.

You wouldn’t want your internal (LAN) address to correspond with your external (WAN) address because first, you want to avoid IP address conflicts. While your router should treat everything on the LAN as totally separate from the outside world, there is the possibility that routing table conflicts could arise. Second, any unsolicited requests that come to the router generally get ignored unless you’ve set up a DMZ host (a computer to where all of the unsolicited incoming traffic goes).

Your router offers your computer a great deal of protection due to the fact that it bears the brunt of the unsolicited internet traffic. You only get the packets that you request, so any random port-scanning malware won’t be able to connect to you.

So, don’t bother with the internal IP settings. There’s really no point unless you’re trying to set up a VPN; and that’s a whole other can of worms.