问题
I make a connection for connect to the Database Server (other machine). Then I found "An error was encountered performing the requested operation: IO Error: The Network Adapter could not establish the connection Vendor code 17002".
Please look the picture in URL below.
I tried to make a connection but can't access but my team can access it. My friend used TNS connection type and I did everthing similar him but can't access. I tried to use JDBC thin for connect but can't also.
I had the old connection which I can connect but why I can't connect the new connection.
回答1:
You're trying to connect to a machine on a network that SQL Developer is unable to reach.
For a TNS connection, Look at the appropriate TNSNames entry (you will have a tnsnames.ora) file, and find the IP address or network name associated with the connection you're trying to establish -
And then start by trying to ping that resource.
In this case, i'm trying to talk to a database on MY machine, on port 1521. Yours should look quite different.
If you're using a basic connection, then you can look at the connection properties and see what machine/port you're trying to communicate with.
Ping
If you can't reach that machine from your machine, there's zero chance you can connect to a database there.
So, always start with a ping.
Once you see that you can get to that machine, if you're still getting that message, the next thing to think about is blocked ports, the listener defaults to port 1521, but you'll see that in the TNS descriptor as well.
来源：https://stackoverflow.com/questions/58746972/what-is-the-cause-of-this-problem-io-error-the-network-adapter-could-not-estab