方法1：sudo echo 1 > /proc/sys/net/ipv4/ip_forward
方法2：sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"
方法3：sudo sysctl -w net.ipv4.ip_forward=1
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cat /proc/sys/net/ipv4/ip_forward
sudo sysctl -w net.ipv4.ip_forward=1
sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"
iptables -nL -t nat
sudo iptables -t nat -A PREROUTING -p tcp --dport 5554 -j DNAT --to-destination 192.168.1.18:554
sudo iptables -t nat -A POSTROUTING -p tcp -d 192.168.1.18 --dport 554 -j MASQUERADE
sudo iptables -t nat -A PREROUTING -p tcp --dport 8080 -j DNAT --to-destination 192.168.1.18:80
sudo iptables -t nat -A POSTROUTING -p tcp -d 192.168.1.18 --dport 80 -j MASQUERADE
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#sudo iptables-save > /home/xx/iptables.txt
sudo iptables-restore < /home/xx/iptables.txt
sudo iptables -F
sudo iptables -X
sudo iptables -t nat -F
sudo iptables -t nat -X
sudo iptables -t mangle -F
sudo iptables -t mangle -X
sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT
