Oracle TNS Listner problem on Internet

[mupendra]

We have a router NATing a public IP to a private IP where the oracle server connected to the private IP. We did NAT the port 1521 to private IP port 1521.


When we are trying to access the server from outside our office through port 1521 we are getting an error TNS Operation Timed Out. It is working fine when we try to connect internally in our LAN.

Can somebody help us.

Thanks in advance for your help

 

[Turkbear]

There is a configuration parameter in the listener I believe, that prevents the default Oracle listener's action of changing the port to some other one after responding to the initial 'call'...


Look into the docs on Network administration and firewalls..

 

[thormax]

We are having exactly the same issue. I have had many ideas floated by me to fix the problem. So far none have worked. I found one person who had the same issue and he sent me what he did to fix it. But I won't be able to test this until Thursday. I was wondering if you found out anything else. I will gladly help you and maybe in the process we can help each other.

 

[greekgirl]

Can you please explain how this was fixed. I am having the same TNS operation timed out errors.

 

[thormax]

Greekgirl

Our problems resulted from improper router coding by our Cisco programmer. I went through each of the routers and reprogrammed the NAT properly and then we had no more TNS operation time out errors. We were utilizing a VPN and the NAT settings were incorrectly programmed.

 

[DBAwhosaysNIE]

not to be too harsh about this but why are you exposing an Oracle instance directly to the internet? there are known buffer overflow attacks (though there are patches for the known ones) on the TNS Listener.

if you can't afford a VPN I'd at least use ssh tunnels.

putting an instance directly on the internet (even w/NAT) is not a good idea...

 

[greekgirl]

Directly connected to the internet?? I'm connecting via sqlnet using Oracle clients software to connect to the server. Obviously I travel over the internet to get to the server which sits behind a firewall.
I have installed the known patches for buffer overflow.
I cannot use a VPN, the current setup is as it is -- Harshness accepted.

Thormax, Could you please expand on the NAT settings/reprogramming.

 

[Turkbear]

Hi,
Just a reminder -
Port 1521 is just used by the listener to 'accept' a request for a connection to the database instance.
After connecting the session, it goes away and all further communication ( in Oracle's default setup) is by way of a randomly assigned port #...

I believe Oracle's Connection Manager can handle problems caused by this behavior..