[Ti] Ethernet Connection Problem

[Amara Lynn Graps]

Dear Titanium Mac folks,

This is my first post to the list (hi!), unfortunately it is because
I have a problem that I do not know how to solve.

I have a PowerBook G4, 15", late 2002 model, 1GHz, 133 MHz Bus speed.
I am using Mac OS 10.3.9 This computer is a used-new Mac I bought
about 3 months ago and is my primary work computer, so I am a bit
desparate.

This afternoon, suddenly (changing nothing on my
computer), the Ethernet port is not functioning properly. I worked
with the sys admin people trying a number of tests since I thought
it was a problem with the local area network. The System Preferences
Built-In Ethernet configuration are correct because the Sys Admin
people can 'see' packets from my computer, that is, they can see
when I turn it on, and when I ping the router or other computers.

However, on my end, nothing returns when I try to ping, or connect
to the Ethernet in any way. Pinging always returns a 100% packet
loss; other ways I tried to connect to the Internet via ssh, ftp, 
http etc. all find 'no nodename' (even though I have the proper 
DNS server IP set in the Network Manual Setup).

The computer is acting as if I have a 'firewall', however I wouldn't
even know how to do that, or how it might have gotten into such a
mode. If this is a hardware problem, then how is it possible that
the Sys Admin people can 'see' when I turn on my computer and try
pinging?

Any ideas for what is causing my nonConnect?

Thanks in advance...

Amara

P.S. Unfortunately I don't have access to another Ethernet network
for about a week or so (when my home DSL becomes active), in order
to check my computer with a different network.

P.S.S. If you are wondering how I sent out this message, I'm using
a different nonMac computer for this message.
-- 

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Amara Graps, PhD        www.amara.com
Istituto di Fisica dello Spazio Interplanetario, CNR - ARTOV, 
Via del Fosso del Cavaliere, 100, I-00133 Roma, ITALIA
tel: +39-06-4993-4375      fax:  +39-06-4993-4383
Amara.Graps at ifsi.rm.cnr.it http://www.mpi-hd.mpg.de/dustgroup/~graps/ 
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"We came whirling out of Nothingness scattering stars like dust." 
--Rumi