client/server security

I know this was discussed in the past in reference to ops$login (and I certainly would not mind a summary of that thread) but can any tell me how they handle oracle security from a pc running sqlnet and connecting to a unix oracle database? These same people will also want to connect from a unix system and wont want to enter a password.

Also, how are people using ops$name to facilitate user logins and does this compromise the database security?

Thanks for any help or suggestions,
Mark Citron

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Mark Citron
mark_at_neurosci.usc.edu