title: Error while connecting to Oracle database from oracle SQL Developer though I've the oracle client installed
body: <p>I've installed Oracle client in my machine, when I'm trying to connect to the oracle database server from Oracle SQL Developer am getting the following error: </p>
  
  <pre><code>Status : Failure -Test failed: IO Error: The Network Adapter could not establish the connection
  </code></pre>
  
  <p>But am able to connect to the server using sql plus and TOAD as well from my machine. What is the issue if Toad connects to the server why cant my Oracle sql developer could not connect??</p>
  
  <p>checked all the possible solutions like:
  tns strings checking, telnet to the server and its port, 
  changing the oracle home in the sqldeveloper->tools->preferences->database->advanced tab.</p>
  
  <p>None solved my issue. Is this the firewall issue?
  If it is so how am able to connect using TOAD/sql plus ??</p>
  
  <p>UPDATE: I'm connecting to the Oracle database server using the VPN.</p>
  
  <p>Any help is much appreciated.</p>
  
  <p>Thanks in advance.</p>