Losing internet when second wifi adapter enabled ...

Question

I have two Wifi LANs in my house. One is on 192.168.1.0/255.255.255.0 which is routed through my boadband gateway/router to the internet. The other is 192.168.0.0/255.255.255.0 and is routed through a Linksys WRT54GS router, which connects two desktop PCs through wired connections and the Inspiron through Wifi. The desktops connect to the internet over their own separate USB wifi adapters.    All works OK on the laptop with access to the desktops OR the internet depending on which network I connect to from the internal wifi adapter, from the 'view available networks' ... But being a lazy sod ;) I decided to install a USB Wifi adapter onto the Inspiron so that I could simultaneously connect to both networks. However  it only works intermittently. Both networks connect OK, and I can ping either router/gateway, but generally once I am connected to the LAN I cannot access the internet. Once I disconnect or disable the linksys routed LAN the internet works straight away. But once I reconnect to the  Linksys LAN then the internet is lost again (but the connection to the router/gateway and ability to ping stays ... I cannot ping out onto to internet).   I reckon (perhaps) that internet explorer (the os) is getting confused in some way and is trying to see the internet over the linksys LAN, but doesn't then continue to try on the other one once that fails.   The odd thing is that it does work sometimes ... It worked for a few hours this morning, but after a reboot it hasn't worked since ... despite various attempts.   I can't find anything in 'internet properties' that allows me to tell the os to only look on the correct adapter ... but maybe there is something out there ...   Anybody any ideas ....   Thanks,

Greg16 · Answer

They're on different channels right?

CmA · Answer

No ... both wifi's are on 7 ... but if this is a problem, then why does it work for hours at times with both adapters connected, and then fail for further hours!! Although the linksys LAN seems to take priority, and always works. The reason for using the same channel is it allows me to simply change over my configuration ... ie I don't always connect the two adapters to the laptop, and so  can easily switch between networks from the single internal adapter in the laptop ...

Greg16 · Answer

OK. The first thing you will want to do is seperate the channels of the two networks, preferably to 1 and 11, or as far apart as possible. The way wi-fi was designed, two different networks on the same channel will interfere with each other, especially when they transmit. It might work occasionally, but there will be tons of dropped packets. This might not be the only issue, but it is certainly the first step to resolving the problem.

CmA · Answer

Thanks for that Greg ... I guess some reconfig is on the cards!! Appreciated ...

CmA · Answer

Changed channels ... no change!

But I opened up the adpater properties that connects to the internet and tried opening google.ie. It didn't open (despite active connection to the bb modem) AND there was no traffic on the link!! Did a ping from a DOS prompt and there was link traffic. So this looks like something in the OS (or IE properties) that is directing internet traffic down the wrong adapter ... The gateway on the link is the modem, which I thought is what is needed to direct the traffic ... (Not an expert, so could just be something simple that I have missed).

???

CmA · Answer

I could ping the modem, and see the traffic going over the adapter/link ... but when I tried to open IE on www.google.ie (or whatever) then there was no link traffic over that adapter at all ... so it seemed to be looking for the internet from IE over the LAN adapter ... Hope I've made it clearer this time ...

Greg16 · Answer

Rather, you weren't able to view the google web page, but you could ping it.

Greg16 · Answer

So, you were able to ping google from the command prompt, but not from ie?

CmA · Answer

Got it in one ... Impressive ... ;-)   I was thinking over the last hour that maybe it is just a DNS lookup problem, so I'll try accessing google.ie directly from an IP address and see what happens ...

Greg16 · Answer

Just to help me understand your setup: (correct me if i'm wrong)

1: The cable modem has a built in wireless gateway

2: The wrt54gs is not directly connected (wired or wireless) to the gateway

3: Nothing is connected by ethernet to the modem

4: Now, the wrt54gs and the modem/gateway are on different wireless channels

5: if you inplugged the 2 USB wi-fi adapters from the desktops, they would be off the internet, but the LAN would still work.

Thanks!

CmA · Answer

I manually set the 192.168.0.* adapter (connected via linksys) to 192.168.0.5, and no gateway. All now working ... could be fluke, but we will see ...

I somehow think the gateway setting could be directing the traffic (and I don't understand this stuff in particular!) down the wrong adapter ... and confusing IE and the OS ... just an idea ...

CmA · Answer

double post deleted Message Edited by CmA on 10-19-2005 08:24 PM

CmA · Answer

Tried pinging www.google.ie direct to its IP address ... no difference ...   I wonder is there some sort of 'hello' packet coming down the LAN from one of the two desktops from their internet connections that is making the laptop think the the internet is accessible via the linksys connected wifi adapter, rather than the modem connected adapter ... Still think it is probably something simple ... these things often are ... Arrrrrgggggg .... :)

Greg16 · Answer

Why don't you just hook up the internet port of the wrt54gs to the modem, turn off the modems wireless gateway, and let all your computers use wireless for everything? The LAN will still work, and you wont have to use 2 wireless adapters all of the time on you 9300.

Greg16 · Answer

Hmm. The wrt54gs does have a firewall built in but if you are looking for another solution, I would try smoothwall, which will turn a spare computer into a dedicated firewall.

Networking, Internet, & Bluetooth

Losing internet when second wifi adapter enabled ...

Was this post helpful?