<p>I am interacting with an Oracle DB using SQL over an ODBC connection.  Is there an SQL command I can use to get the MAC address of the server, or something that uniquely identifies the server hardware or software installation.  This is so I can be sure (or at least fairly sure) that I'm talking to the same database all the time.</p>

I don't know if you could get the mac address at all. But there are several informations which may help you at the v$instance view.
```
```
SELECT * FROM v$instance;
```
```