How can I use the login monitoring tool?

It is not very easy to use the login monitoring tool passively. If the connection is not encrypted you might try adding a host "in front of" the database server, that will be able to intercept the Oracle conversations. A simple presentation here. Wireshark is able to intercept and decode traffic (user and machine), so that and some filtering script can intercept the connections themselves. To be able to log other traffic statistics, you'd need to write a specific application using libpcap. That's all hacking, however. The "true" solution would be to work with the DB server accounting system. The hack version has the advantage of being passive, i.e. the server sees nothing amiss, and does not consume resources to perform logging and reporting; they are done in the sniffing "front end".