Even if I don't see clearly why you want to limit table access by IP rather then by username, here's a possible solution.
I don't have a database now to test it, so you should try it on your own ... :-)
1. Set up a driving policy with CREATE OR REPLACE CONTEXT ...
2. Create the package associated with the context you defined in step 1.
In the package: Set the context, and define the predicate
3. Define the policy as SYSDBA by using DBMS_RLS.ADD_POLICY.
4. Set up a logon trigger to call the package at logon time and set the context
Use ORA_CLIENT_IP_ADDRESS to identify client's IP address.
1. CREATE OR REPLACE CONTEXT my_ctx
2. CREATE OR REPLACE PACKAGE my_pkg
IS...here you get the client's IP with a procedure or function... I'd recommend to read about DBMS_SESSION.SET_CONTEXT procedure, too!
3. Define the policy as SYSDBA by using DBMS_RLS.ADD_POLICY procedure
4. CREATE OR REPLACE TRIGGER set_ctx_on_logon
AFTER LOGON ON DATABASE...
I hope you can work it out now!
But why do you want to limit table access by IP?!