Failure Modes of Networking Tools?

Bijan Parsia bparsia at email.unc.edu
Tue Dec 18 13:24:58 UTC 2001


On Tue, 18 Dec 2001, Andrew C. Greenberg wrote:

> So, I was browsing along happily in Scamper when I loaded up a website 
> that seemed to confuse it.  Afterwards, I was unable to load ANY 
> website.  Checking further, I noted that name resolution was freezing 
> without return for domains that should have worked fine.
> 
> So, just to be sure, I saved the image,

Just *asking* for trouble! ;)

> checked networking on the 
> machine itself.  All was well.
> 
> Restarted the image, same deal.  Network installed OK, and the 
> NetNameResolver reported status 1 (ready).  But a simple netname 
> resolution failed again by freezing.

There's at least two points to consider: network initializaiton and name
resolution. These are only combined on your first attempt to resolve a
name. Socket class>>initializeNetwork (or NetNameResolver
class>>initializeNetworkIfFail:) would help isolate the problem.

[snip]
> So the problem appears network related and image-specific.  How can I 
> fix the old image?  I'm not sure what even to check.  Any thoughts?

A few:
	Do plain ip addresses work? Again, this would help isolate the
		problem.
	It's still possible, *think* for Sockets to avoid finalization. It
		may be worth doing a Smalltalk garbageCollect, then Socket
		allInstances and poke around.
	It might be worth initialize NetNameResolver, thought I don't see
		that that does all that much.
	Hmm. Make sure you don't have the Scamper instance hanging around.

Hope something helps ;)

Cheers,
Bijan Parsia.





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