Help to understand firewall commands for Netgear/Voxel openvpn client

[kamoj]

I appreciate if someone can explain what these iptables commands do, and why Netgear's and Voxel's differ:

Netgear R7800-V1.0.2.46:
iptables -I INPUT -i tun0 -j ACCEPT
iptables -I OUTPUT -o tun0 -j ACCEPT
iptables -I FORWARD -i tun0 -j ACCEPT
iptables -I FORWARD -o tun0 -j ACCEPT
iptables -t nat -I POSTROUTING -o tun0 -j MASQUERADE

Voxel R7800-V1.0.2.50SF:
iptables -I INPUT -i tun0 -j ACCEPT
iptables -I OUTPUT -j ACCEPT
iptables -I FORWARD 2 -i tun0 -j ACCEPT
iptables -I FORWARD -i br0 -o tun0 -j ACCEPT
iptables -I FORWARD -i tun0 -o br0 -j ACCEPT
iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE

 

[Voxel]

I appreciate if someone can explain what these iptables commands do, and why Netgear's and Voxel's differ:

Netgear R7800-V1.0.2.46:
iptables -I INPUT -i tun0 -j ACCEPT
iptables -I OUTPUT -o tun0 -j ACCEPT
iptables -I FORWARD -i tun0 -j ACCEPT
iptables -I FORWARD -o tun0 -j ACCEPT
iptables -t nat -I POSTROUTING -o tun0 -j MASQUERADE

Voxel R7800-V1.0.2.50SF:
iptables -I INPUT -i tun0 -j ACCEPT
iptables -I OUTPUT -j ACCEPT
iptables -I FORWARD 2 -i tun0 -j ACCEPT
iptables -I FORWARD -i br0 -o tun0 -j ACCEPT
iptables -I FORWARD -i tun0 -o br0 -j ACCEPT
iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE

Well, kamoj, I cannot say that I am expert in iptables...

Voxel.

 

[kamoj]

And from DD-WRT yet another way of doing it:

iptables -D POSTROUTING -t nat -o tun1 -j MASQUERADE
iptables -I POSTROUTING -t nat -o tun1 -j MASQUERADE
iptables -D INPUT -i tun1 -j ACCEPT
iptables -D FORWARD -i tun1 -j ACCEPT
iptables -D FORWARD -o tun1 -j ACCEPT
iptables -I INPUT -i tun1 -j ACCEPT
iptables -I FORWARD -i tun1 -j ACCEPT
iptables -I FORWARD -o tun1 -j ACCEPT