TNS Listener Problems

I'm having a problem that has me totally stumped:

Oracle 8.1.6 on a P-III 650 laptop with 256 MB memory, Windows NT4SP6.

I do development work at a customer site as well as the office, and sometimes "on the road". In all these situations I need to access the local database instance on the laptop. When connected to the office network, everything works fine. However, when I am disconnected from the network, OR connected to a client network, I am unable to connect to the local laptop instance. The error is always "ORA-03113 End of file on communication channel". This happens regardless of whether I use TCP/IP or IPC.

I strongly suspect the problem has to do with DNS and IP addresses/name resolution. However, I have changed the listener.ora and tnsnames.ora to use 127.0.0.1 and 'localhost' as addresses, without affecting the symptoms. I.e., even using 127.0.0.1 or localhost, it works when physically connected to my home network, but not when disconnected or on a different network. I'm defining "home network" as the one I was connected to when I installed Oracle. It's almost as if Oracle decided which DNS servers to use when it was installed, and is ignoring changes. Also, it seems to want to use DNS even when using IPC.

Here are some scenarios, showing the results of attempting to connect to the LOCAL database instance on the laptop:

1. Boot up on home network (DHCP provides IP address and name servers) ==> SUCCESS
2. Disconnect network cable ==> ORA-03113
3. Reconnect network cable ==> SUCCESS
4. Leave network cable connected and do "IPCONFIG /release"
   ==> ORA-03113
   
5. Without rebooting, do "IPCONFIG /renew" ==> SUCCESS
6. Boot system "on the road" (i.e. no network connection at all) ==> ORA-03113
7. Boot system with network card removed ==> ORA-03113
8. Boot up on foreign network with DHCP... Get different IP address/name server ==> ORA-03113. Note, in this situation I AM able to connect to databases on other servers on the foreign network... just not to MY OWN local instance.

Anyone have any suggestions?

I have a bunch of admin-level traces of various scenarios, but there's nothing obviously different between the successes and failures. Also, there's nothing interesting in the NT event log.

-- 
James Garrison                                Athens Group, Inc.
mailto:jhg_at_athensgroup.com                    5608 Parkcrest Dr
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