after upgrading from version 7.2 to 8.0(4), clients couldn't connect to the database through the firewall using Toad software but they can connect using SQL.
I checked the firewall and found some dropped packets in inspect sqlnet.
I disabled sqlnet inspection and the clients can connect.
The next day some clients reported that the database applications isn't working, I checked the firewall and found some denied connections on ports other than 1521
What is the problem, Please help