DHCP problem

hmmm, this is very strange.

My home network consists of a DSL modem hooked to a 4-port router with 3 computers hooked directly to it, and then a wireless router hooked to the first router acting essentially as a WAP/switch.

Now the problem... My Asus Z63a laptop will not acquire an IP via DHCP. this just started today, even though the network has been operating totally fine for months.

If I connect the laptop via ethernet and manually configure the IP address the connection works fine, both connected directly to the first router and connected to the wireless router through one of its ethernet ports. I haven't actually tested the wireless connection configured manually, but my adapter picks up the SSID no problem and begins trying to acquire an address as normal.

I thought perhaps this was a problem with the first router's DHCP server, but every other computer on the network is able to acquire an adress without problem.

Anyway, I'm stumped. If you have any suggestions, I welcome them.

 

Hi,

Firstly you need to establish whether its the laptop thats causing the problem or the wireless. If you have another laptop or wireless system, try connecting, if it works then your problem will lie in ur laptop. Try connecting your laptop to other wireless networks, if that works, then it might be your wireless router.

Have you tried manually configuring the IP address on the wireless connection??

That might help.

 

Also make sure that the router and the DSL modem are allocating IP addresses out of different network pools.

For instance, if the DSL modem is using DHCP with a network of IP addresses ranging from 192.168.1.1-192.168.1.254, you do NOT want the router to allocate addresses from and subset of the first range.

Recommended settings would be something like this:
DSL Modem DHCP Pool - Network ID: 192.168.x with subnet mask 255.255.255.0
Router DHCP Pool - Network ID: 192.168.y with subnet mask 255.255.255.0
JUST MAKE SURE THAT X DOES NOT EQUAL Y.

If you have a question as to what the DHCP settings of the DSL modem are, go to start->run->type cmd, in the popup window type in ipconfig /all on one of the PCs that are directly connected to the DSL modem. That should give you the settings for the PCs IP address and the subnet mask.

Just make sure the router addresses are using IPs that are significantly different from what you get from the ipconfig /all command.

Hope that makes sense...pulling a late night tonight.

 

Actually if you were gonna set up the network as it sounds to me, you would want only 1 DHCP router, any more would confuse the laptop, as it would try and aquire 2 IP addresses.

 

you should turn dhcp off on the second router as well as making sure to not use the wan port. Oh and statically set the IP for the second router, make sure on the same subnet. I would recomend getting a true WAP as using a router seems to screw things up. I had a setup like yours til I got fed up with it and went out and bought a wap. Now everthing is much simpler.

 

ok, my bad... all computers are connected to a router, none are connected to the DSL modem. 3 computers are connected directly to the first router, then the wireless router is connected via one of its LAN ports (as in not the WAN port). The wireless router has its DHCP server disabled.

The thing is, this setup as I describe it has worked flawlessly for at least 6 months. I haven't changed any settings on any of the routers or on my laptop, so as to what has happened, I have no idea. Basically, I have tried all combinations of connecting, including hooking directly via ethernet cable to the router hooked directly to the modem, and I cannot get DHCP to acquire.

 

oh, and the wireless connection works fine if I manually configure the IP/subnet/gateway

 

that was a good run. I got my similar system to work for about 2 months and then crapping out. I went with a real WAP for $79 (linksys) and have been running perfect for several months now.

Technically you need to use a crossover cable to connect similar devices (i.e switch to switch, pc to pc, router to router). Make sure that the router has the main router as a gateway and if all IP/subnets are config correctly then you might as well face to thought of getting a new router. Im assuming your using the normal retail equiment and not high end commercial stuff, and they have a significantly low lifespan, especially when you combine a siwcth/router/WAP/DHCP server all in one low priced peice of hardware. Check out the linksys WAP, they are the cheapest Ive seen and all youll need to do is config IP/subnet and your set. Plus they have a cisco trade up progranm if you so desire.

 

i've conencted router to routers and router/wireless gateway without the need for crossover cables, i agree PC to PC you need them, but i dont think you need them for router to switch.

BIGV if it works fine by manually configuring the settings, then it sounds to me like you dont have DHCP system on ur wireless, make sure that there is a DHCP server on your wireless network, adn that its turend on. Or, just enter the manual settings and leave it at that.

 

You don't need crossover cables PC to PC either, if the ports are auto-sensing. Most network ports are anymore, but not completely. If his network was working at all, then that means that his setup was correct.
As for DHCP not working, I've run into that a time or two, but it was usually just a router reboot to fix it. Sorry

 

no it is required for two devices of the same type i.e router to router , pc to pc and switch to switch. But now that I re think things he is connecting the router to the switch part of the router therefore does not need a crossover. Because technically the router is a switch and router in one device.

 

what really has me stumped is that even if I plug the laptop directly to the router which is connected to the modem, DHCP does not work. However, the 3 other desktops which are also connected to that router have no problem using DHCP. I think what I'll do is try my laptop on one of the other ports on the router and see if DHCP will work. If not, I guess there's something buggered with my system... somehow.

 

well, I powered down both routers again and then started them back up. somewhere between the two of them, things started working properly again.