A system for verifying caller ID information in received VoIP calls. In particular implementations, a method includes receiving a caller identification (ID) identifying a calling party telephone number in a call initiation message transmitted from a VoIP call agent; determining the identity of the VoIP call agent; verifying that a public switched telephone network (PSTN) call to the calling party telephone number would arrive at a VoIP call agent having the determined identity; and applying, responsive to the call initiation message, one or more rules based at least in part on the verifying step.