How can I connect to Oracle Database 11g server through ssh tunnel chain (double tunnel, server in company network)?

Question

I have SSH access to \'public\' server, which is also the gateway to company network. There is another server in the network, where local Oracle Database se

Answer 1

I had the same issue as @j_maly here in comments, it is possible to connect using just one tunnel to the "GATEWAY" doing this in "MY REMOTE PC" (linux):

ssh -L 1521:DATABASE_URL_OR_IP:1521 USER@GATEWAY

But after getting ORA-12170: TNS:Connect timeout occurred over and over again. I've done this:

• In GATEWAY, connect something against oracle that works, in my case, sqldeveloper (sqlplus should work too). Let's guess the oracle working url in sqldeveloper is database.company.ex

• In GATEWAY run netstat -putan | grep 1521, and here is the issue:
  I found that connection has other database ip and domain than the previous known and supposedly connected (database.company.ex).

• So You should put the ip or url showed in the result of netstat -putan | grep 1521 in "GATEWAY"

  ssh -L 1521:DATABASE_URL_OR_IP_SHOWED_IN_NETSTAT:1521 USER@GATEWAY

I don't know why this happens exactly, but I found several ips to connect to the same database, and I can't connect from some of them, to solve the problem we must find the correct ip.

It's important to mention that you could also change the local port (11000 in this case) and run this command with no output (-fN)

ssh -fN -L 11000:DATABASE:1521 USER@GATEWAY