ssh加固 限制root用户直接登录 sed -i "s#PermitRootLogin yes#PermitRootLogin no#g" /etc/ssh/sshd_config systemctl restart sshd 修改允许密码错误次数 sed -i "/MaxAuthTries/d" /etc/ssh/sshd_config echo "MaxAuthTries 3" >> /etc/ssh/sshd_config systemctl restart sshd 关闭AgentForwarding和TcpForwarding sed -i "/AgentForwarding/d" /etc/ssh/sshd_config sed -i "/TcpForwarding/d" /etc/ssh/sshd_config echo "AllowAgentForwarding no" >> /etc/ssh/sshd_config echo "AllowTcpForwarding no" >> /etc/ssh/sshd_config systemctl restart sshd 关闭UseDNS sed -i "/UseDNS/d" /etc/ssh/sshd_config echo "UseDNS no" >> /etc/ssh/sshd_config systemctl restart sshd