One of our Oracle databases is running on RedHat Enterprise Linux 5.3. Listener is running on 1521
But I can connect to the database only from server itself. From no other machines I can connect to my database. IPTables is blocking them on 1521.
So, I’m adding a new rule to IPTables so any traffic to 1521 is allowed.
I added the rule, saved the rule and restarted the IPTables service.
Saving and restarting is not required to have the rule to be active but
better not to let the rule forgotten.
iptables -I INPUT -p tcp –dport 1521 -j ACCEPT
Now, it works. I can connect from other machines