A bridged gateway coupled to a local area network (LAN) receives a layer 2 frame from a device coupled to the LAN. The bridged gateway forwards, to a network gateway router that provides layer 3 routing services for the LAN, the layer 2 frame via a layer 2 tunnel. The bridged gateway determines that the layer 2 frame comprises a dynamic host configuration protocol (DHCP) discover message, the DHCP discover message including an initial message in a four message sequence used by the network gateway router and the device to provide an internet protocol (IP) address to the device. The bridged gateway determines that the four message sequence between the device and the network gateway router did not complete. The bridged gateway, in response to determining the four message sequence did not complete, sends, to a destination, an alert that comprises information indicating a problem with the network gateway router.