Hmmm...I've been having a similar problem with some ES40s. When they
first boot up and try to ping them I get a "network unreachable" as
well. The strange part is, if I telnet to them I can get there and
after I do that I can ping them as well. I'm not sure what it could
be. I think I was having the same problem on the ES40s with the tulip
dirver as well. All with the stock drivers in the 2.2.10 kernel. If
I have time, maybe I'll see if I can put some diagnostics in the
driver and see if I can figure out what the problem is.
One thing that I found on the Miata is that once in a while the
networking would fail and come back. I couldn't find anything in the
logs. When this happens, if I unload the module and load it again it
would be fixed immediately. Of course, if you do this you lose all
the open connections you had.
If you can figure out the problem, let me know how to solve it.