A method of a device for filtering messages routing across a network includes extracting, by a filter configured on the device, a plurality of message components from messages received via a network. The plurality of message components is identified as having at least a field name in common, including a first field name. A learning engine configured on the device creates a list of data types for values of the first field name. The list includes one or more data types of a value of the first field name identified for each of the plurality of message components. The learning engine determines a most restrictive data type from the list of data types for the values of the first field name of the plurality of message components.