TNS配置正确，而tnsping不通

TNS-03505: Failed to resolve name

TNS配置正确，而tnsping不通，可能会有以下原因；

查看：/oracle/product/9204/network/admin/sqlnet.ora
cat /oracle/product/9204/network/admin/sqlnet.ora

/oracle/product/9204/network/admin $cat sqlnet.ora
# SQLNET.ORA Network Configuration File: /oracle/product/9204/network/admin/sqlnet.ora
# Generated by Oracle configuration tools.

NAMES.DEFAULT_DOMAIN = localdomain

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)

将 NAMES.DEFAULT_DOMAIN = localdomain屏蔽，
问题解决。