Generic networking question - loss of connection

Forum: Networking
Topic: Generic networking question - loss of connection
started by: john.martzouco

Posted by john.martzouco on Dec. 19 2007,03:46

I've got some understanding of iwconfig, ifconfig, route, traceroute... but that's about as far as my network information utilities goes. I could use a couple of quick pointers to other tools or concepts to research because I need to fix a small problem we're seeing with both our laptops.

Using wifi WPA and connecting to our AP fine. Every once in a while, we lose connection with the network and I don't know how to get it back. When this happens, the other laptop is working fine, so I know that our AP, router, modem are all okay. When I reboot the disconnected machine, it gets back on the network without any trouble.

What information can I get from dmesg, route, iwconfig, ifconfig etc after the machine has disconnected so that I can figure out what has gone wrong on the machine?

Thanks,
John

Posted by jpeters on Dec. 19 2007,08:35

Quote (john.martzouco @ Dec. 18 2007,22:46)

When I reboot the disconnected machine, it gets back on the network without any trouble.

What information can I get from dmesg, route, iwconfig, ifconfig etc after the machine has disconnected so that I can figure out what has gone wrong on the machine?

Thanks,
John

It's most likely an issue with the having to update the IP. I haven't had this problem running DSL, but someone else using a windoz OS on the same wireless will suddenly lose the connection and need to reboot....they also require running the "repair" function, which appears to clean out all the old connection data and start fresh.

Posted by john.martzouco on Dec. 19 2007,11:24

Quote (jpeters @ Dec. 19 2007,03:35)

... someone else using a windoz OS on the same wireless will suddenly lose the connection and need to reboot....they also require running the "repair" function, which appears to clean out all the old connection data and start fresh.

Hi J,

Yes, I remember that ipconfig /release, ipconfig /renew is the way to ask for a new IP address from the DHCP server in Windows. I'm sure Microsoft is offering these as high-level commands that are doing a combination of route del default; route del ...; pump -i ath0; etc etc (I'm not sure of what all the steps would be).

I should have mentioned that I'm using static IP addresses on all of my machines, so the IP addresses are the same when the disconnect occurs as they are when the machine is rebooted a minute later.

Posted by john.martzouco on Dec. 22 2007,00:18

I had a bit of good luck with this issue tonight...

With these 3 steps, I was able to reconnect to my WAP:

1) killall wpa_supplicant
2) [restart wpa_supplicant] with login values
3) [execute ifconfig and
route add using the wlan0.sh file generated by DSL]

Would it help me to monitor wpa_supplicant so that I can find out if it's the cause of the disconnect?

What shell commands would be helpful to monitor it?

Thanks,
John

PS - I'll be asking a question in a minute or two about how to set up a guest user to be able to execute a script for this without giving them sudo priviliges.