A method for an intermediate node to independently locate whether a fault of sending a packet from a first end node to a second end node is related to the intermediate node, wherein the intermediate node serves to forward the packet between the first end node and the second end node, the method comprising: creating, by the intermediate node, a test packet and sending the test packet to the first end node, wherein the test packet comprises address information of the second end node, and the test packet is used to trigger the first end node to send a response packet destined for the second end node to the intermediate node; forwarding, by the intermediate node, the response packet from the first end node to the second end node; capturing, by the intermediate node, the response packet; and analyzing, by the intermediate node, according to a result of the packet capturing, whether a packet from the first end node to the second end node is able to be forwarded normally, including determining that the intermediate node cannot forward the packet from the first end node to the second end node normally, if the number of the response packets received from the first end node is not the same as the number of the response packets sent to the second end node, or the difference between the number of the received response packets and the number of the sent response packets does not fall within an error range, or if the delay between receiving and sending the response packets does not fall within a normal delay range; wherein: the test packet further comprises address information of the first end node, the second end node address serves as a source address of the test packet, and the first end node address serves as a destination address of the test packet; wherein the response packet is generated according to the source address of the test packet. creating, by the intermediate node, a test packet and sending the test packet to the first end node, wherein the test packet comprises address information of the second end node, and the test packet is used to trigger the first end node to send a response packet destined for the second end node to the intermediate node; forwarding, by the intermediate node, the response packet from the first end node to the second end node; capturing, by the intermediate node, the response packet; and analyzing, by the intermediate node, according to a result of the packet capturing, whether a packet from the first end node to the second end node is able to be forwarded normally, including determining that the intermediate node cannot forward the packet from the first end node to the second end node normally, if the number of the response packets received from the first end node is not the same as the number of the response packets sent to the second end node, or the difference between the number of the received response packets and the number of the sent response packets does not fall within an error range, or if the delay between receiving and sending the response packets does not fall within a normal delay range; the test packet further comprises address information of the first end node, the second end node address serves as a source address of the test packet, and the first end node address serves as a destination address of the test packet; wherein the response packet is generated according to the source address of the test packet.