It is definitely not a local problem. It is the router setting that restricts ICMP from having ports such as TCP or UDP, but it does contain two domains: type and code. Moreover, the functions and ports of these domains are completely different. Some netizens said: ping does not specify port options, right? It belongs to the network layer, but the port is the concept of the transport layer. The Ping program uses the ICMP protocol, and ICMP is not like _ unreachable or timeout ————————————————————————————————————————————————————————— The ping content is a sending and receiving packet, which is not in the application layer and has nothing to do with the port, right? ! The problem party added: this must be related to the port I blocked. I don't close the port. Normal. It will not PING after it is set to only allow the above ports to be opened. I don't think the firewall installed in the system can find the PING port. So let me ask. I only changed the firewall settings of the router. The set port is the port on the first floor —————————————— Check the firewall. Have ICMP-in and ICMP-out been turned off? Generally speaking, the firewall will turn off ICMP first. ICMP is in the network layer, while TCP/UDP is in the transport layer. ————————————————————————————