Various communication systems may benefit from appropriate filtering of communications. For example, a network having a broadcast bus, such as a controller area network, may benefit from a frame filter. For example, a method can include receiving a plurality of messages at an interface with a broadcast bus of a communication network for a system. The method can also include selectively permitting the plurality of messages to be conveyed through the interface based on comparing one or more of the plurality of messages to a specification for the interface.