Re: Remote connection through NAT

You need to add port address translation or port mapping.

NAT effectivly masks everything inside your local lan from the rest of the internet allowing anyone from inside your network to interact with the outside world, but to the rest of the world your Lan looks like a single IP address which may or may not have a relationship with the public IP address, when in reality there may be a lot of different machines behind your router. Each with a private ip address..

NAT takes requests from inside your lan and translates them at the router leaving a reply socket in a table for socket communication to work then removes it when done, It appears to only open a space when the request comes from inside your lan.

For instance I have a machine at 10.0.0.1 and I make a nat call throught the gateway to a server in the outside. say, telnet port 23. My machine may have aquired my socket as 1030 so 10.0.0.1 port 1030 is then talking to the someserver.com port 23. This is stored in the router linking someserver port 23 to 10.0.0.1 port 1030. The telnet conversation happens, then the connection is closed and the entry dissapears. This is the way Nat works.

Now what you need is port address translation. So that when a request comes from the outside world the packets are routed to the designated machine. Lets say your public wan IP address is 204.204.205.9, whenever a a packet appears there which is marked for the database listener by a port number, this needs to be routed to the machine on the lan where the database lives.

The port number is the then the designated port number or numbers that the listener is listening on. This is typically 1521 for oracle but there may be other ports used as well. These ports should be listed in the listener.ora file.

So have your sysadmin open up the Sisco port and route packets to your db machine.

Steve finkelman

Christ Follower wrote:

> In our environment, we have a remote db that the db server can be
> reached only through SISCO NAT TCP forward. The listener on that server
> is running on a different (internal) IP that NAT would forward traffic
> to. I am not able to use SQL*Plus to connect to that server. What
> configuration change do I need to do? Thanks.
>
> Danny
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
Received on Wed Nov 10 1999 - 15:37:48 CST