iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -j SNAT --to-source 172.16.1.1

echo 1 > /proc/sys/net/ipv4/ip_forward　　永久：vi /etc/sysctl.conf  修改： net.ipv4.ip_forward = 1　然后 sysctl -p /etc/sysctl.conf 

iptables转发