listener connection time out question

This is very wierd to me but I don't know if it has something to do with Personal Edition of Oracle 8i, installed on Mandrake 2.4.8.

I started server by "lsnrctl start". then everything is ok. I tried jdbc thin connection from outside LAN, and it works fine. However, I must keep that jdbc program running. If i stopped that jdbc program for a little while, the network connection will fail.

java.sql.SQLException: Io exception: The Network Adapter could not establish the
 connection at
oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:168)

I checked the listener log, everything is OK, except that the client side get the above message. When I am trying jdbc connection from inside LAN, I never have that problem. does anybody know why? Received on Sun Feb 17 2002 - 20:29:57 CET