tnsnames.ora
contains the mappings tnsnames.ora
in the following locations: $TNS_ADMIN/tnsnames.ora
$ORACLE_BASE_HOME/network/admin/tnsnames.ora
$ORACLE_HOME/network/admin/tnsnames.ora
$TNS_ADMIN
environment variable exists, but does contain have a tnsnames.ora
file, the file is assumed to be missing and Oracle NET will not try to find it in other directories. tnsnames.ora
contains one or more entries in the following format: NET_SERVICE_NAME = ( DESCRIPTION = ( ADDRESS=( protocol_address ) ) ( CONNECT_DATA = ( SERVICE_NAME=service_name ) ) )
protocol_address
is used to locate and contact the listener. service_name
to the listener which in turn will then try to locate and contact the specified Oracle service SERVICE_NAME
corresponds to the global database name specified when the database was created. foodb.somewhere.xyz
corresponds to the database name foodb
and the domain name somewhere.xyz
. SQLNET.AUTHENTICATION_SERVICES
has leading blank spaces. extproc_connection_data
used to call external procedures? TNS-03505: Failed to resolve name | Unable to contact the listener specified in the (DESCRIPTION…) section of the connect descriptor. |
ORA-12154: TNS: could not resolve the connect identifier specified | The listener could be contacted but it was unable to contect the service specified in the (CONNECT_DATA…) section |
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor | The listener could be contacted but it is not configured to handle the service specified in the (CONNECT_DATA …) seciton |
ORA-12518: TNS:listener could not hand off client connection | |
ORA-12560: TNS:protocol adapter error | |
ORA-03135: connection lost contact |
trcasst
: the trace assistant for Oracle Net Services trace files.