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raspi/Quick Linux iptables NAT.md

Last active July 20, 2022 17:13
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Quick NAT with GNU/Linux iptables firewall
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Quick Linux iptables NAT.md

Quick NAT with GNU/Linux iptables firewall.

First set static IP for LAN adapter:

ip address add 192.168.99.1/24 dev LANeth0

Enable packet forwarding:

echo 1 > /proc/sys/net/ipv4/ip_forward

Set NAT firewall rules:

iptables -t nat -A POSTROUTING -o WANeth0 -j MASQUERADE
iptables -A FORWARD -i WANeth0 -o LANeth0 -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i LANeth0 -o WANeth0 -j ACCEPT

Now this machine can be used as gateway. On other machine(s):

ip route add default via 192.168.99.1
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