The technology disclosed herein enables the enforcement of firewall policies based on high level identification strings. In a particular embodiment, a method provides receiving a first reply from a first identification system directed to a requestor system. In response to determining that the first identification system comprises an identification system trusted by the firewall, the method provides inspecting at least one packet included in the first reply to identify a first network address therein associated with a first high level identification string. The method further provides updating a data structure comprising allowed network addresses with the first network address and, after updating the data structure with the first network address, allowing at least one packet from the requestor system directed to a first destination at the first network address to traverse the firewall system based on the data structure.