A configuration file for the client or server that specifies the:
Client domain to append to unqualified service names or net service names
Preferred order of naming methods that the client should use when resolving a name
The sqlnet.ora file must reside in one of the following locations:
The directory specified by the TNS_ADMIN environment variable If the TNS_ADMIN environment variable is not defined as a variable on Windows NT, it may be in the registry.
Oracle Net Services Configuration Overview
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