[SOLVED] Network often fails at boot

[russell.eberhardt]

Hi,

For about two weeks now I've had an intermittent problem with both my laptop and desktop machines (specs below):

Both machines intermittently fail to connect to my router on boot, the desktop connects via ethernet and the laptop via wifi.  When the network fails to come up I can usually connect by going to "Configure network" and just running through with the existing settings, if that fails I have to reboot.  Start the connection at boot is ticked of course.
The desktop is running Full Monty with kernel 2.6.38.8-pclos1.pae.bfs, the laptop 2011.6 with kernel 2.6.38.8-pclos1.bfs, both fully updated.

The router is fine, if I boot into Win XP or another Linux distro it connects every time.

I have tried adding "service network restart" to rc.local to no avail.  I have also run memtest on both machines with no errors.

Any ideas?

Russell.

[menotu]

Hi Russell, Have you considered removing the network connections completely - rebooting and re-adding?

Alternatively dropping down a kernel (kernel-2.6.37.4 or similar) to see whether it's specific to the 38.8 kernel.  Of course, keep the 2.6.38.8 kernels in place so you can switch back if desired.

[russell.eberhardt]

Hi Russell, Have you considered removing the network connections completely - rebooting and re-adding?

Yes, already tried that.

Alternatively dropping down a kernel (kernel-2.6.37.4 or similar) to see whether it's specific to the 38.8 kernel.  Of course, keep the 2.6.38.8 kernels in place so you can switch back if desired.

Thanks, I should have thought of that.  Tried it and rebooted a couple of times - so far so good.  Problem with these intermittent faults is you never know if you have fixed it.

If it doesn't recur in the next few days I'll mark it "Solved".

Russell.

[menotu]

If it doesn't recur in the next few days I'll mark it "Solved".

Fingers crossed 

[Jonesy]

I am assuming your router is wireless?. In your router config assign a default channel number manually until you get a stable setup. It is almost certainly set to auto right now and therein most likely lies the problem You have no idea how many laptops I have had to look at for friends with this very issue recently. Window$ setups seem to fair even worse than Linux

The problem seems to stem from very poor selectivity and image rejection in the wireless protocol in some routers.
A good indication is to check what networks show up in Manage Networks. If your own router is only showing say 20% and the guy 200 yards down the street is lighting up at 90% there's the problem right there.

The network failing at boot is probably not your PC. But if your hard wired then I dunno 

[muungwana]

you should have looked at "/var/log/syslog" log file after you boot up and things dont work. There is probably a clue in there why things dont work when they dont. Your investigation in this matter could increase the general knowledge of the forum and may be useful to somebody else sooner or later.

[russell.eberhardt]

I am assuming your router is wireless?.

My router is hardwired to the desktop machine (ethernet) and wireless to the laptop.  Both have been showing the same symptoms since an update about a couple of weeks ago.

It looks like Menotu was right - problem with the latest kernel.

Russell.

[russell.eberhardt]

you should have looked at "/var/log/syslog" log file after you boot up and things dont work.

Thanks.  I,ll go back to the latest kernel in a few days and have a look.

Russell.