①开启服务器

#cd /usr/local/sbin

#./opensipsctl start

#/etc/init.d/opensips  start

(#service opensips status)

②firewalld防火墙

#systemctl stop(start) firewalld.service

#sudo firewall-cmd --state

③ufw防火墙

#sudo ufw disable(enable)

#sudo ufw staus

④进行ssh连接之前，先开启该服务

#service sshd start