[PLUG] Can a faulty wifi driver affect router's behavior?

Mayuresh mayuresh at acm.org
Sun Dec 4 03:09:49 PST 2011


I find this strange:

Have been using wifi network on Fedora for a long time. Following two
things happened fairly frequently (2/3 times a day) and I had started
considering it as `normal':

1. The desktop/laptop dropping the connection (with no apparent trigger,
except perhaps multiple sessions demanding data over network
simultaneously), in which case you must manually do ifdown and ifup again.
It won't re-connect automatically.


2. Desktop/laptop showing connection active with good signal quality, but
router simply not responding to anything - even ping to it. In this case
there was no option but to power restart the router and after it comes up
again restart the interface.


This was painful, though I had come to terms with it.

Then NetBSD appeared out of blue on my laptop/desktop one fine day.


The wifi driver on NetBSD for my hardware is so stable, it never dropped
the connection over last few months of usage. Even if the router is
switched off and on, the interface remains active and re-establishes
connection automatically.

So far still nothing unusual. One implementation of driver can be better
than the other.


What surprises me is the issue no. 2 above, where I had to occasionally
restart the router as it used to get hung has disappeared as well.

Can a flaw in a wifi driver jam/hang a router? If that were the case, one
can deliberately jam wifi drivers. One would expect routers to be more
stable than that. Or is it just one off vulnerability with the router
firmware, accidentally exposed by a bug in a driver. (Highly unlikely
coincidence.)

Mayuresh.



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