It looks like this "fan-map 250.0.0.0/8:172.17.0.0/16" in ip command is the cause, there will be no error if you just run "ip link add ftun0 type vxlan id 16384000 dev docker0 dstport 0 local 172.17.0.1 "
It looks like this "fan-map 250.0.0. 0/8:172. 17.0.0/ 16" in ip command is the cause, there will be no error if you just run "ip link add ftun0 type vxlan id 16384000 dev docker0 dstport 0 local 172.17.0.1 "