Question: I was trying to connect to Oracle through
SQL developer, and I see this error.
io exception: the network adaptor could not
establish the connection
Vendor code 17002
Answer: In your case the "Vendor code 17002"
is the equivalent of the ORA-12541 error: It's most likely that
your listener is down, or has an improper port or service name.
From the docs:
ORA-12541: TNS no listener
Cause: Listener for the source repository has not been
Action: Start the Listener on the machine where the source
Basically, SQL Developer could not find the listener. First check the
tnsnames.ora file and ensure that it points to the correct server and
port. If the Forms server is on another machine, test the TNS resolve
from the command prompt. Finally, check the
# lsnrctl status
This should show the status of the listener and the services it is
listening for. Remember that when you run SQL*Plus on the database
server, it does not need the listener to connect unless you specify the
database tnsnames.ora entry.
You can use the lsnrctl status
command to verify that the
listener is down, and lsnrctl start
to start your listener. If
you are on Windows, also verify that the listener service is running.