Abstract: Framework for countering VoIP SPAM. The framework is applicable to all sessions sending out the spam from an outbound domain to a inbound domain, in which the outbound domain and the inbound domain respectively has: a spam prevention system for detecting whether an outbound call is spam and blocking the call if needed; a spam prevention policy server for adding, modifying, or deleting spam countering policies being applied to the spam prevention system; and a call server for making or receiving a call, in connection with the spam prevention system.