NAMES.ORA Network Configuration File: /u01/app/oracle/product/8.1.7/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.

college=
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost.localdomain)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SID =college)
    )
  )

[oracle@localhost 10.2.0]$ vi tnsnames.ora
[oracle@localhost 10.2.0]$ tnsping college

TNS Ping Utility for Linux: Version 10.2.0.1.0 - Production on 14-OCT-2011 14:37:22

Copyright (c) 1997, 2005, Oracle.  All rights reserved.

Used parameter files:

TNS-03505: Failed to resolve name

TNS-03505: Failed to resolve name
 *Cause:  The service name you provided could not be found in TNSNAMES.ORA,
          an Oracle Names server, or a native naming service.
 *Action: Verify that you entered the service name correctly.  You may need
          to ensure that the name was entered correctly into the network
          configuration.