e740 WiFi can't connect to internet

[schamberlin]

My e740 connects to my home wireless LAN fine, and can ping other wireless devices in my home, but it can't ping to my wireless router or connect to the internet. Any ideas what I could be missing?

I've configured the wireless LAN Utility settings (Infrastructure, ANY), and it shows it's connected to my home LAN with the correct IP address (192.168.1.101) and gateway (192.168.1.1). The LinkSys router clients table also shows that the Toshiba has been given the DHCP address 192.168.1.101. Using vxUtils on the Toshiba, I can successfully ping two other wireless devices (a laptop and a TiVO system). I can also ping the Toshiba from the laptop.

The problem is that I get no conncectivity between the LinkSys router and the Toshiba. The Toshiba can't ping the router, and nothing on the wired LAN can ping the Toshiba. The laptop and TiVo both connect wirelessly through the router to the internet with no problems.

This makes no sense to me, since the router and Toshiba clearly had to communicate to establish the wireless connection and do the DHCP setup, which all worked fine. But once it gets to actually sending some real data, all goes silent.

Is this a known problem that might be cured with a software update or other work-around? Is there other diagnostic software that might help narrow the problem further?

[Janak Parekh]

That is indeed really bizarre. Apart from checking whether or not there is a ROM update for the Toshiba and/or the Linksys, I'd suggest doing things like turning off WEP, turning SSID broadcast on, etc. It doesn't sound like that's your problem as the wireless clients all talk to each other, but I'm saying it just for the sake of it. ;)

Also, if you have a friend with a WLAN, it might be worth bringing the e740 over there to see if you can narrow down the possibilities.

--janak

[schamberlin]

I set up a packet sniffer on the wireless laptop, and a second one on my desktop PC, to try to understand what's happening.

When the laptop attempts to ping the desktop PC, it first sends an ARP request asking who has that IP address. The request is copied from the wireless to the wired ethernet, then the desktop replies, and the reply is copied from the wired to the wireless ethernet. Finally the laptop receives the reply, and starts sending ICMP packets.

When the PDA attempts to ping the desktop PC, it also sends an ARP request asking who has that IP address. The request is copied from the wireless to the wired ethernet, then the desktop replies, BUT the reply is never copied from the wired to the wireless ethernet. It's not that the PDA fails to receive the reply, but the reply was never even sent out over the wireless (as proven by the packet sniffer running on the laptop).

The only difference between the ARP reply that got copied to the wireless ethernet and the one that didn't is the destination MAC address and IP address. So it seems like my wireless router is swallowing up all traffic that should go to my PDA.

[Janak Parekh]

When the PDA attempts to ping the desktop PC, it also sends an ARP request asking who has that IP address. The request is copied from the wireless to the wired ethernet, then the desktop replies, BUT the reply is never copied from the wired to the wireless ethernet. It's not that the PDA fails to receive the reply, but the reply was never even sent out over the wireless (as proven by the packet sniffer running on the laptop).
Right - there's a nonzero chance the router is the culprit.

The important question, of course, is why only for the PDA? Moreover, it doesn't sound like you did a packet sniff for pings between the PDA and the laptop. Any results there? In that case, the base station is merely replicating the signal and not bridging it between the two segments.

The only difference between the ARP reply that got copied to the wireless ethernet and the one that didn't is the destination MAC address and IP address. So it seems like my wireless router is swallowing up all traffic that should go to my PDA.
Another interesting idea would be to see if you can change the PDA's MAC address, although you really shouldn't have to. You don't have MAC filtering turned on on your base station, right? (Although, if you did, the PDA shouldn't even associate with the base station in the first place.)

--janak

[schamberlin]

I tried everything I could think of with the PDA and the router settings, including resetting the router to factory defaults. Finally I purchased a new Netgear router that's virtually identical to my Linksys, and now it works like a champ.

Very strange...