Approaches, techniques, and mechanisms are disclosed for implementing a distributed firewall. In an embodiment, many different computer assets police incoming messages based on local policy data. This local policy data is synchronized with global policy data. The global policy data is generated by one or more separate analyzers. Each analyzer has access to message logs, or information derived therefrom, for groups of computer assets, and is thus able to generate policies based on intelligence from an entire group as opposed to an isolated asset. Among other effects, some of the approaches, techniques, and mechanisms may be effective even in computing environments with limited supervision over the attack surface, and/or computing environments in which assets may need to make independent decisions with respect to how incoming messages should be handled, on account of latency and/or unreliability in connections to other system components.