Wireless routing trouble

Question

I just installed arch on my new desktop PC, among a series of trouble this is my last one that I cannot find a way to resolve.
Once every hour to once very few minutes, with a duration of under 2-3 minutes, my box will refuse to send stuff to the gateway (which is also the access point I use), but still send stuff to the other computers thru the same access point.
I got to this conclusion after starting 3 pings in background: router, intranet computer, external host (yahoo.com).
When this weird phenomenon occurs, I will get replies form the intranet computer, but not from the other 2 pinged hosts.
I am sure it's not a router issue because I have also ran these 3 ping scenarios on a machine connected by ethernet and on my laptop (arch, same wireless configuration as the PC with the problem, except that it's a iwl3945 driver), both work fine in the same time my desktop PC fails.
Another weird thing I have noticed, is that when I get these timeouts, if I do a "sudo route", it will print my subnet route, but hang before printing my other route (the one with the gateway). (Just to be clear, this only happens while I get the timeouts. After the normal operation resumes, route will finish the output instantly). This hang can be upto a minute.
There is nothing new in /var/log/messages during this phenomenon.
I have also noticed that if I restart the wpa_supplicant process, the timeouts occur less often for an hour or so.
Does anyone know what's causing this?
Here's my "route" output:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.100.0 * 255.255.255.0 U 0 0 0 wlan0
default 192.168.100.1 0.0.0.0 UG 0 0 0 wlan0
I have the following wireless card:
03:01.0 Network controller: RaLink RT2561/RT61 802.11g PCI
Subsystem: RaLink EW-7108PCg
Flags: bus master, slow devsel, latency 32, IRQ 22
Memory at f9ff8000 (32-bit, non-prefetchable) [size=32K]
Capabilities: <access denied>
Kernel driver in use: rt61pci
Kernel modules: rt61pci
I use it to connect to a WPA2-PSK wifi (hidden ssid, AES encryption).
I connect to the wireless with the following script:
wpa_supplicant -Dwext -iwlan0 -c /etc/wpa_<wifiname>.conf -dd &
dhclient wlan0
Here's the .conf I use:
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
ap_scan=1
update_config=1
network={
scan_ssid=1
ssid="<the_ssid>"
psk=the_wpa_key
This works. Lan is up, inet is up.
Last edited by Frantic (2009-02-25 17:48:36)

Answer 1

Yep, there are actually a lot more computers running on that same AP.
When I was checking to make sure it's not a problem with the router I used the troublesome PC, my laptop and a intranet server over SSH. There are alos 10ish computers running at the same time on that same intranet at the same time.
What happens to me is that I can access anything else on the intranet except the gateway.
I don't have to restart it, it will eventually fix itself, but I noticed that if I do restart wpa_supplicant it will get fixed instantly and I get a lot less trouble for a short while.
I do have the ethernet NIC that is up but idling, now that you mentioned it, it's up and running, but no wire, might be that causing the trouble.
What I have tried was to negate both interfaces in rc.conf (!wlan0 !eth0), this didn't help. I'll also try doing a ifconfig down eth0.
Funny thing is that I'm running the same configs on my laptop, eth0 up, connecting thru wlan0, same apps, no special configs I know of, working right.