To troubleshoot & diagnose Oracle connectivity problems, follow this checklist:
- Check with "ping" using the IP address ("ping 220.127.116.11"
- Check with "ping" using DNS name (e.g. "tnsping uranus")
- Try telnet to the IP on port 1521 (telnet 18.104.22.168 1521)
- Check with "tnsping" using TNS service name
- Invoke SQL*Plus from the OS command line "sqlplus fred@flintstone". If this fails, check to ensure that your listener is the flintstone service defined.
- Sign-on to SQL*Plus and connect with the TNS name ("connect fred/flintstome@service_name" )
- Within SQL*Plus, try a select from table@remote_db_lin