We have a Sun solaris 9 server (say A), with oracle 9 installed and running, at one place(say X).

We have installed oracle client in windows machines and accessing the database through one application developed by our software vendor. The windows machines are connected through LAN in which the sun server in connected.

we have one more sun solaris 9 server (say B), with oracle 9 installed and running, at another place (say Y) (approx 400 Kilo meters away). This "B" server is connected with "A" server through router => Leased Line > Router => LAN.

At one particular day we do NATting in such a way that the request to IP of "A" server was redirected to "B" server. During this period when we try to access the oracle or tnsping the oracle it says "TNS-12535: TNSperation timed out". we tried to connect to the server "B" with oracle port 1521 from command prompt using telnet it says "Connecting To 'IP add of A server' ...Could not open a connection to host on port 1521 : Connect failed"

We contacted our network team to arrive at a solution. They have connected one separate switch for one windows client and the switch is connected through a separate modem and a separate ISDN line ("because we are on the same LAN connecting from separate line will solve the issue" told by our network team). But still we cannot connect to oracle from the application as well as through "sqlplusw".

If we remove the NAT and connect to the actual IP of server B from location X through telnet to oracle port 1521 it gets connected.

We don't have any firewall at both ends. Our network team says that all ports are open; nothing is blocked.

Please anybody provide a solution.