The invention relates to a method for monitoring, at the correct time, TTEthernet (TT) messages communicated by a TTEthernet switch (TTE switch) in a distributed real-time computer system. According to the invention, the TTE switch has a global time having precision P and accuracy A, and the TTE switch has a plurality of communication channels and one or more monitoring channels, and the TTE switch contains a selection data structure that specifies which TT message classes are to be monitored, and a copy of a TT message which belongs to a TT message class selected for monitoring is formed in the TTE switch and is transmitted by the TTE switch via a monitoring channel to a monitoring node, and the TTE switch subsequently autonomously transmits an ET message containing an identifier and the exact transmission time of the monitored TT message via a monitoring channel to a monitoring node.