What should I do if the ssh connection is slow? Xshell is slow to connect to the virtual machine?

What should I do if the ssh connection is slow? Xshell is slow to connect to the virtual machine?

Simply turn off UseDNS

vi /etc/ssh/sshd_config
将 #UseDNS yes 改为 UseDNS no
然后重启ssh服务
#centos7 
systemctl restart  sshd.service
#centos6 
service sshd restart  

Reconnect the virtual machine