Linksys BEFSR41 - imopressions and questions

[d1abolic]

Just came back from the store with a Linksys BEFSR41. Thanks to all that recommended this to me in my other threat - so far it works great. Had it up and running in <5 minutes. Anyway, i noticed that i now have a new IP. How exactly did the router do that? Can i manually edit my IP and make it whatever i want (assuming it isn't taken that is)? If i can't set the exact IP, can i somehow reset it to simply change my IP?

 

[Epsil0n00]

<< Just came back from the store with a Linksys BEFSR41. Thanks to all that recommended this to me in my other threat - so far it works great. Had it up and running in <5 minutes. Anyway, i noticed that i now have a new IP. How exactly did the router do that? Can i manually edit my IP and make it whatever i want (assuming it isn't taken that is)? If i can't set the exact IP, can i somehow reset it to simply change my IP? >>



I have this router and love it! The router acts as a gateway to your computers, thus it takes the IP that was assigned to you by your ISP and uses it for the router. Then, it uses DHCP to assign a (somewhat) random IP address to all of the systems connected to it. You cannot manually edit the IP address assigned to a specific system. There is a certain range of IPs that your router will assign, I think it is from 192.168.1.1 to 192.168.1.255. If I remember correctly you can set the range of which numbers to use and what number to start at. I set my range to a max of 2 IPs starting at 192.168.1.100. Thus, one of my systems is that IP and the other is 192.168.1.101. However, from outside my LAN you would not be able to access my computers by sending data to those IPs. To reach me, you would have to send data to the IP of my router. This is due to another function call NAT which is Network Address Translation. This takes the traffic coming from my individual comptuer (with the aforementioned IP) and packages that traffic in the IP address of my router. Thus, no matter how many computers I have on my LAN it looks like I only have one.

I hope that makes sense, please respond if you have more questions. 🙂 I am no expert, but I think the above info is a good basic explanation.

 

[Dan]

Epsil0n00: Well done. That's a great explanation of what's going on with the router. I have the same model and IMHO it's fantastic.

 

[dawbs]

Hello,

This is some what of an answer to your question too....

You can have one (1) IP address seen from the out side by using... DMZ in the advanced configuration.

This is from Linksys's WebPage


Q:What is DMZ?
A: Demilitarized Zone (DMZ) allows one IP Address (computer) to be exposed to the Internet. Some applications require multiple TCP/IP ports to be open. DMZ Q: If DMZ is used, does the exposed user share the public IP with the Router?
A: No.

allows just one computer to be exposed for that purpose. It is recommended that you set your computer with a static IP if you want to use DMZ.


Just to let you know... 🙂

I have this router and it works really good in my current setup.

dawbs

 

[kgraeme]

Epsil0n00 got most of it. The Linksys box does a few basic functions:

1. Switch: This is what lets computers on your local network talk to each other. A switch differs from a hub in that it makes sure that a computer only talks to the one other computer it needs to instead of slamming everything on the network. This is completely automatic with the Linksys.

2. Router: This is the traffic cop that makes your network seperate. When you plug a computer directly into a cable modem you are part of a large network. A router logically divides your local network off so that when your computers talk to each other, they aren't slamming everything else on the wider network. A router isn't the same as a firewall though because while it is a way to segment the network, it's like an entrance to a residential comunity with a just a name sign instead of a guard post for a gated community.

3. DHCP server: This allows you to plug a computer into your network and have it automatically get an appropriate IP address. DHCP is "Dynamic Host Control Protocol". This is specifically what you asked about. By default, the DHCP server is turned on in the Linksys and it's configured to hand out addresses starting at 192.168.1.100. You asked about changing IP addresses and you can, but with some caveats. First off, you should only pick addresses that fit the agreed upon range for private networks. 192.168.x.x is one of those ranges. You can choose to let the Linksys box assign all IPs. You can turn off its DHCP router and set IPs manually. Or your can mix. So you could have the DHCP server assign up to 50 addresses starting at 192.168.1.100, while at the same time setting a local server computer with a manual address of 192.168.1.10. Notice that the server's manually assigned IP isn't in the same number range as the DHCP addresses.

When you restart a computer with a dynamically assigned address, there is a chance that the address it gets will be different than what it was before. This can be a bad thing if you have a game server or something on your network and it's why you might want to assign it an address manually. A print server is another example. Basically, any server should have a fixed IP.

4. NAT: This works in partnership with the router and DHCP server. The router has segmented your network, but it's still open. Your computers on your local network have a different IP than what is handed out from your ISP. The NAT acts as the signboard to tell packets coming into your network which computer they should be delivered to. Just like an apartment building has a single address, but each unit has a unique number.

5: Firewall: A partnership of Router and NAT. It's the front desk guard that looks to see if a packet has an appointment. With the Linksys router though it's possible to set up a public reception room that the guard can direct people to. They call it the DMZ.