关闭portmapper服务

Portmapper服务被利用发起Ddos攻击，所以需要禁用。
rpcinfo -p

   program vers proto   port  service
    100000    4   tcp    111  portmapper
    100000    3   tcp    111  portmapper
    100000    2   tcp    111  portmapper
    100000    4   udp    111  portmapper
    100000    3   udp    111  portmapper
    100000    2   udp    111  portmapper

systemctl stop rpcbind
systemctl stop rpcbind.socket

[root@s-a ~]# rpcinfo -p
rpcinfo: can't contact portmapper: RPC: Remote system error - Connection refused

systemctl disable rpcbind
systemctl disable rpcbind.socket