A network device checks forwarding tables of routers in a network by sending check packets designed to reach a target router via label-forwarding. The network device determines a forwarding path from itself to a destination IP address, with the target router on the forwarding path and at N hops from itself. The network device then generates and sends a check packet having a label stack with N link labels correspond to the hops and a TTL value set to N+1. When the check packet is routed by the target router to a next-hop node of the target router, the TTL value is deducted to 0, causing the next-hop node to send a notification message to the network device. Based on the identity of the next hop node, the network device determines whether the forwarding table of the target router is correct.