A host operating in a managed environment intercepts a call from a managed caller to a particular callee and determines whether the call is permissible according to the host's prior configuration of a plurality of callees. The particular callee, which provides access to a resource that the host can be protecting, can have been previously configured by the host to always allow the call to be made, to never allow the call to be made, or to allow the call to be made based upon the degree to which the host trusts the managed caller.