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Posted: Mon May 12, 2003 5:50 am Post subject: linksys wire less routers

I just bought 2 linksys routers one for my office and one for home. The one for the office is attached through my existing hub so only works as an access point. The one at home works great plugged it in, set my laptop to get everything assigned to it automatically and boom up and running in under 5 minutes. The one at work I set up the DHCP so it assigns me the addresses automatically and it seems to work fine the only thing is it only gives me access to all the computers on the network, no internet access. If I hard code in the addresses then I get it all but I don't like the idea of having to go in and add or delete the address info everytime I go from home to work. I want it so that whatever building I walk into it will connect and I can get access to everything

Posted: Mon May 12, 2003 5:57 am Post subject:

Check the DNS server addresses being provided by your DHCP setup at work.

Posted: Mon May 12, 2003 6:00 am Post subject:

Thanks for the try but just checked them and they are correct

Posted: Mon May 12, 2003 6:04 am Post subject:

It just occurred to me: why are you using the Linksys at work as a DHCP server? Won't the laptop pick up its DHCP information from your main DHCP box?

Posted: Mon May 12, 2003 6:15 am Post subject:

Sounds like a default gateway problem. What model of Linksys is this? What's the IP info when you use DHCP, and what is it when you hard-code it?

Posted: Mon May 12, 2003 6:22 am Post subject:

I have a cisco router and modem at work but I wanted to add wireless to my wired network. I am trying to run it as DHCP so that It can give me my info so it can be closer to my home network where everything is assigned from the linksys. The ip info is assigning fine with the DHCP I do not know how I can check what DNS or gateway gets assigned to me from the box. Is there a way?

It is the Linksys WRT54G wireless G Broadband Router

Posted: Mon May 12, 2003 6:25 am Post subject:

I understand why you're using DHCP. What I don't understand is why you're using the Linksys box at work as a DHCP server. Do you not already have another DHCP server running at work?

To check what IP info you're being given open up a command prompt on your laptop and type ipconfig /all

Posted: Mon May 12, 2003 6:47 am Post subject:

Thank you very that was incredibly helpfull. before I continue I must say I'm very impressed with this forum I just joined today and they answers I am getting are fast, furious and very helpfull.

It appears that the problem I am getting is that they linksys router is assigning my gateway address to its own ip and not to the gateway address of my network, When I go into the configuration of the linksys it allows me to set the gateway on the main screen (and it is set correctly) but under the DHCP client it only allows me to set the starting IP addresses and the number of sequentials and the dns address. does anyone know how I can get it to set the gateway correctly?

Posted: Mon May 12, 2003 6:54 am Post subject:

in reponse to your other question, my existing network does not run as DHCP all the computers are configured individual with static IP's

Posted: Mon May 12, 2003 7:29 am Post subject:

I don't know the Linksys device in question but, from what I think you're saying, you'll need to try something like this:

Give the WAN side of your Linksys a static IP address in the same subnet as the rest of the network, complete with default gateway of your LAN's gateway, and DNS servers to match the rest of your LAN.

Configure the Linksys to issue DHCP addresses in a completely different subnet altogether.

The laptop should pick up an IP address from the Linksys, and be told that the Linksys is its default gateway. The Linksys should then automatically route traffic to the same DNS servers & gateway that the rest of the LAN uses.

Posted: Mon May 12, 2003 7:29 am Post subject:

P.S. Don't forget WEP. Smile

Posted: Mon May 12, 2003 2:05 pm Post subject:

Bang! Go with Demon on this... spot-on answer!

Posted: Mon May 12, 2003 2:18 pm Post subject:

Okay here is the problem that I am having with following your instructions.

I have my wan configured with a static ip address in the same subnet as the rest of the network complete with the correct gateway and dns servers (I have a computer plugged into the linksys just so I can test that wired with hard coded ip's I can access everything)

I tried to issue the DHCP to issue addresses in a completely different subnet altogether and it did issue them with the gateway of the static ip that I configured into the previous paragraph, it also assigned my dns as I set up in the DHCP page which are my actual DNS. The linksys must not route the traffic to the actual gateway because it assigned the numbers as you said it should but still no joy.

Am I a pain in the ass or what

Posted: Mon May 12, 2003 4:07 pm Post subject:

Well, let's start testing and see where it falls apart.

For the sake of clarity, I'll assume the following... substitute your IP info as needed...

Linksys WAN:
IP: 192.168.1.10
subnet: 255.255.255.0
gateway: 192.168.1.1
DNS:1.2.3.4

Linksys LAN:
IP: 192.168.2.1
subnet: 255.255.255.0
DHCP start: 192.168.2.200
DHCP-DNS: 1.2.3.4

Your laptop should get an IP address of 192.168.2.200

open a command prompt and:

ping 192.168.2.200
ping 192.168.2.1
ping 192.168.1.10
ping 192.168.1.1
ping 1.2.3.4

This does the following: pings the laptop IP addres, then the laptop's gateway (router near-side), then the far-side of the router, then the router's gateway, then the DNS outside of the local network.

Does it fail? If so, where? If you'd like, post your actual IP info and we'll see if there's something we're missing.

Posted: Mon May 12, 2003 4:49 pm Post subject:

Here's a picture which may help to illustrate what I mean. A picture is worth 1,000 words, and all... Smile

Your IP addresses are probably different, but this will serve for illustrative purposes.

Every device in the 10.0.0.0 network (including the WAN side of the Linksys) has its IP address statically configured, with a subnet mask of 255.255.255.0, gateway of 10.0.0.1, and DNS server of 10.0.0.2. The ISP's DNS server addresses may be substituted instead.

The Linksys is configured with a private address (not the WAN side) of 192.168.0.1. It issues IP addresses via DHCP, with a subnet mask of 255.255.255.0, gateway of 192.168.0.1, and DNS server of 10.0.0.2. If the Linksys can function as a DNS relay then one can change the DNS server to 192.168.0.1. As before, the ISP's DNS servers may be substituted instead.

The laptop picks up an IP address from the Linksys. In this example it's 192.168.0.2. It knows that anything destined for any other network outside the 192.168.0.x range has to be routed elsewhere, in this case through the Linksys.

The Linksys is already on the 10.0.0.x subnet. Anything intended for that subnet gets passed to the appropriate device. Anything intended for the Internet gets passed to 10.0.0.1, because 10.0.0.1 has been configured as the default gateway for the WAN link on the Linksys device.

Remember this: the laptop has to know which default gateway to use. It uses the Private side of the Linksys (192.168.0.1). Similarly, the Linksys has to know which default gateway to use. It uses the main LAN's gateway (10.0.0.1). If the Linksys is told that the default gateway for its WAN link is 192.168.0.1 then traffic will go nowhere.

Without knowing your exact IP address details this can only serve as an example. Feel free to adjust the numbers to match your setup.