NAT filtering Option

[Paul Smith]

Researching a menu within my r7800 (with voxels firmware) I could not find an answer to this question and netgear don’t seem to offer any explanation.

Within the advanced settings of the WAN setup there is an option to set NAT filtering to Open or Secured.

for online gaming the Open setting is the only one that will guarantee you get an open NAT time on Xbox/PS4.

However, it is not clear just how “open” this will make you. Anyone any idea what this setting actually does?

 

[kamoj]

You can list all firewall rules and see what changes:

iptables -L --line-numbers

 

[Paul Smith]

You can list all firewall rules and see what changes:

iptables -L --line-numbers

Many thanks Kamoj. There does not appear to be any differences

 

[ColinTaylor]

Try:

iptables -t nat -L -n -v

 

[R. Gerrits]

or if it affects the nat table (instead of the default filter table)

iptables -t nat -L --line-numbers

But from what I can see, it only controls the behavior of one of the iptables modules.
GUI sets nvram setting wan_nat_fitering (guess Netgear made typo). 0 means secured and 1 means open.
And looking in net-cgi binary, it seems to toggle /proc/sys/dni_netfilter/nat_filtering_behavior

 

[e38BimmerFN]

What NAT filers does changes the NAT kind used by the router. Secure means the NAT kind will be Port Address Restricted. When set to open, NAT kind will be Full Cone Nat which is an older NAT used and is a bit less secure then PAR NAT. Most router mfrs use PAR NAT now days. Only NG seems to allow both NATs which is mainly needed if you have two or more game consoles online playing the same game at the same time and you need OPEN NAT across the game consoles and in the game as well. Mostly multi player first person shooter games like CoD:
https://badmodems.com/Forum/viewtopic.php?f=6&t=21

Secure Filter should be used if you only have 1 game console online at one time.