Docker WARNING IPv4 forwarding is disabled. Networking will not work

具体错误

Docker启动Nginx时出现警告信息，宿主机可以通过curl访问，但外部机器无法访问Nginx。

WARNING: IPv4 forwarding is disabled. Networking will not work.

原因

未开启ipv4转发。

查看ipv4转发配置：

sysctl net.ipv4.ip_forward

解决

方法一

echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf
systemctl restart network

方法二

echo "net.ipv4.ip_forward=1" >> /usr/lib/sysctl.d/00-system.conf
systemctl restart network