connecting through a router

Dear sirs:

I have installed Oracle 9i in a W2K server, and I can acces it from any workstation in the LAN (by installing Oracle Client).

I cannot understand why I am not able to connect from an "external" PC with the same Client and configuration.
This external PC is accesing from the Internet through the port number 1521 of the router, which is open and redirected to my Oracle server.

Is this a normal issue? Other databases (like SQL Server) are working fine on that server without doing anything else...

I would be very grateful if somebody can write a line with a comment.

Usual questions:
What kind of errors do you get?
Can you ping the db server?
Can you tnsping the db server?

I can ping the server, succesfully, but the error using the "net configuration assistant / local network service name" is always the same: timed out.

I am afraid I do not know how "tnspinging" to the server.

How are you connecting, maybe you need to check your tnsnames, if it points to the address as it's known on the lan then that won't work.

You may also need to change the authentication in your sqlnet.ora file, I needed to do this so the webserver could get to the db through the firewall.

if you get really desperate I can try as well, I would need ip, sid, username, pwd... don't post it here pm me

tnsping is a command line utility, like ping that allows you to verify if the tnsnames entry is correct and if the listener is up.