Atheros - Network suddenly stops working?

[Twey]

So, here was I, happily using the internet over my Airlink card (device ath0) when all of a sudden my internet slows down to next to nothing. Puzzled, I attempt to ifdown and ifup my device (ath0), and imagine my horror when it failed to get an IP address! This laptop -- running WinXP -- also failed to connect, temporarily, but was fixed in short order. The desktop can see the network OK, and reports its signal as "Good" or "Excellent" in KWifiManager, but will she work? Not a chance. Usually I just get "Determining IP address for device ath0... failed" but if I'm really lucky, I'll see "icmp open socket: permission denied." I thought it might be due to WEP -- it seems very like what you get if you enter a wrong key -- so I disabled that, but no joy.

Does anyone have any ideas as to what might be the problem?

/EDIT: KWifiManager looks like this:
Connected to network: MyNetwork
Access point: <my AP's MAC>
Local IP: unavailable
Frequency [channel]: 2.462 [11]
Encryption: off
You see - connected, but no IP assigned.

[imdeemvp]

Have you check your router settings and do they match with card?

[Twey]

They do indeed.

[Twey]

I googled the "permission denied" message, and found that it was to do with SELinux. I tried running ifup again without SELinux enforcing, and I got the output of a ping, showing three packets being sent to 192.168.0.1 (my router's IP) and all three being dropped.

[Twey]

This is now a confirmed software issue - I booted up a PHLAK liveCD and (after some struggles) got the card connected to the network and working.

[funchords]

I thought it might be due to WEP -- it seems very like what you get if you enter a wrong key -- so I disabled that, but no joy.

This does smell like authentication. The "I can see it but I can't connect" phenomena is a strong hint of an EAP-style (802.1X, WPA, WPA2) lockout.

Do you have wpa_supplicant on your system?

One way to test is to configure your AP with your desired security method and a new SSID. Reboot your system. As it's rebooting, uplug power to the AP and plug it back in. Log into your system.

If you're doing the site scan/survey method, then just connect with it when it appears in the list. Otherwise, create a configuration for it.

What this does is help ensure that some old profile setting or other garbage info stored by the network in some temporary place isn't causing the disruption. Much is keyed off the SSID.

[Twey]

I think it may be something to do with the bitrate of my card. I was fiddling with it earlier, and I actually got it to connect! Then I did something stupid, and let system-config-network touch my config, and it all went again. I'm convinced this is a client-side problem. Changing the AP's SSID didn't help.

[Twey]

On advice, I compiled and installed the latest version of the drivers. It didn't help.

[funchords]

I think it may be something to do with the bitrate of my card. I was fiddling with it earlier, and I actually got it to connect! Then I did something stupid, and let system-config-network touch my config, and it all went again. I'm convinced this is a client-side problem. Changing the AP's SSID didn't help.

Hey Twey,

This reminded me that the same thing happened to me.

The system-config-network screwed up the rate on my card!!


Here is my /etc/sysconfig/network-scripts/ifcfg-ath0 ... hopefully it can be of help to you...

# Please read /usr/share/doc/initscripts-*/sysconfig.txt
# for the documentation of these parameters.
IPV6INIT=no
ONBOOT=yes
USERCTL=yes
PEERDNS=no
GATEWAY=192.168.177.251
TYPE=Wireless
DEVICE=ath0
HWADDR=00:11:95:e7:6e:26
BOOTPROTO=dhcp
NETMASK=255.255.255.0
DHCP_HOSTNAME=
IPADDR=192.168.177.103
DOMAIN=
ESSID=
CHANNEL=1
MODE=Managed
RATE=Auto

[Twey]

After some fiddling with the latest drivers -- and not touching system-config-network or even ifup with a bargepole -- I managed to get a very tenuous connection that crashed if I tried to receive data over TCP, and cut out every so often. In the end I gave up and reinstalled Fedora 32-bit, the drivers for which, I'm glad to say, are much more stable.