According to one aspect, the subject matter described herein includes a system for Diameter routing and firewall filtering. The system includes a Diameter signaling router comprising a network interface for receiving, from a first Diameter node, a first Diameter message having Diameter information. The Diameter signaling router also includes a firewall module for determining whether the first Diameter message satisfies a firewall policy. The firewall policy is based on at least a portion of the Diameter information in the first Diameter message. The Diameter signaling router further includes a routing module for forwarding at least a portion of the first Diameter message towards a second Diameter node in response to the first Diameter message satisfying the firewall policy.