A method for operating a router or a firewall device connected between at least two networks, the at least two networks comprising communication networks, system networks or computer networks and designed for allowing data traffic to pass between the at least two networks or to block a passage of data traffic through the router or firewall device, depending on adaptable and correspondingly activated data traffic rules, wherein the router or the firewall device has an integrated component that provides a communication relationship recording functionality for recording communication relationships present during the passage of the data traffic, the method comprising:
- temporarily activating and deactivating the recording functionality for recording communication relationships with at least one of:
- a START/STOP button in a web-based management of the router or the firewall device,
- injecting a signal into a predetermined digital signal input connection of the router or the firewall device, and
- an external central management tool,
- and
- after conclusion of the recording of the communication relationships and only after having deactivated the communication relationship recording functionality, processing recorded communication relationships for adaption and subsequent activation of the data traffic rules.