For ASM, Dbvisit Replicate uses bequeath connection and therefore has to use the ASM home as the client and sets the ORACLE_HOME accordingly (setup wizards asks for the ORACLE_HOME when ASM is in use).
For all other Oracle connections, Dbvisit Replicate uses SQL*Net connections. As it comes with it's own Oracle client, it has to be told where to look for sqlnet.ora/tnsnames.ora files. Setup wizard will ask for TNS_ADMIN.
In order of precedence:
- The DDC setting TNS_ADMIN can be used to select the correct configuration files.
- TNS_ADMIN can be also specified in the environment.
- The DDC setting ORACLE_HOME also selects the correct configuration files; note that this is set if ASM is in use.
- ORACLE_HOME can be also specified in the environment.
- Current directory is searched last.
These are standard Oracle precedence rules, with the only addition that DDC file can override variable specified in the environment.