DSL Modem & Router configuration

[lignit]

Hi :
I have a broadband Connection for which my ISP has provided a Broadband Modem.I connect the phone line to this modem. The modem is connected to the Laptop/PC using the RJ45. The modem has an IP of 192.168.1.1 , which I changed to 192.168.1.100 , on the same subnet mask 255.255.255.0 . Everything works fine.DHCP is enabled.

I have a wireless router.When I connect the modem to the router and the router to my PC, I can ping the router(default IP of 192.168.1.1 changed to 192.168.1.33) . This router is DEHCP enabled. I cant seem to connect to the net under this configuration.

I can ping my router and that's the farthest I could get.For the moment, I have disabled the Wireless connection and instead connected the PC to the router using another RJ45.

Can someone point me in the right direction.What shd I be doing to get 2 computers use the internet simultaneously?

Cheers
Lig

[DerekH]

Welcome to WebmasterWorld, lignit.

It's hard to understand exactly what you have there, but I'll tell you what I've got - it sounds similar...

I have a Mac connected via Ethernet to an ADSL router modem that connects me to the Internet.

My wife bought a wireless Mac that's now in another room.
I plugged an airport wireless base station into the router.

In order for the system to work properly, I have had to turn OFF DHCP in the base station so that it acts transparently, and I had to connect the "server side" of the airport base station to the router.
Without turning off DHCP, it was impossible to share a printer or see each others computers, because there was always two address translation steps between the two computers. With this, there is one - the IP address of my wife's Mac is not concealed by the wireless basestation, and instead is allocated by the router's DHCP server.

There are some good PDF files on the Apple Website that show you how to connect wireless routers to Ethernet routers. Search their site for
designing airport networks
The PDFs will explain all about DHCP and NAT (with diagrams, which is what we can't do here!)

Once set up, it *will* work seamlessly!

DerekH

[BjarneDM]

1) DHCP servers. It's generally a very very bad idea to have two of these on the same subnet, so you'll have to turn one of them off. Otherwise you can get into some very interesting conflicts.

2) Wireless routers.
When you add a wireless router with DHCP enabled to an existing network, you usually (but not always - it depends on the default settings) get another subnet with the computers that connect through the wireless router. Eg. the first subnet gets IP-numbers in the range 192.168.1.1-192.168.1.254 and the second one gets IP-numbers in the range 10.0.0.1-10.0.0.254. These two subnets are unable to see each other even though both of them are using the same *dsl router/modem to connect to the internet.
On the other hand, turning off the DHCP server in the wireless router makes your entire network visible to everyone who's able to connect to your wireless router. This is one hell of a security/privacy problem unless you make damned sure that you've turned one every security measure and are using strong passwords.