Unless you’ve gone out of your way to disable the H.263 NAT ALG, NAT actually allows websites and other services to open either random ports on your machine (if using business firewalls) or ports on any device on your network (many consumer routers).
If your router allows you to disable SIP ALG and H.263 ALG, you should. If it doesn’t, well, maybe they’ve been patched? If you’ve applied a kernel firmware update to your router the last 1-2 years you may be safe (though not many vendors will bother updating the kernel when updating their routers). You’ll lose access to SIP phones and some video calling services over IPv4, but at least some Javascript on a random blog won’t be able to hack your printer.
This wouldn’t work with IPv6, as these two protocols just work with IPv6 (and IPv4, as it was designed). ALGs are hacks around protocols, rewriting packets to make all of the problems NAT causes go away.
Unless you’ve gone out of your way to disable the H.263 NAT ALG, NAT actually allows websites and other services to open either random ports on your machine (if using business firewalls) or ports on any device on your network (many consumer routers).
If your router allows you to disable SIP ALG and H.263 ALG, you should. If it doesn’t, well, maybe they’ve been patched? If you’ve applied a kernel firmware update to your router the last 1-2 years you may be safe (though not many vendors will bother updating the kernel when updating their routers). You’ll lose access to SIP phones and some video calling services over IPv4, but at least some Javascript on a random blog won’t be able to hack your printer.
This wouldn’t work with IPv6, as these two protocols just work with IPv6 (and IPv4, as it was designed). ALGs are hacks around protocols, rewriting packets to make all of the problems NAT causes go away.
More info on this here: https://www.armis.com/research/nat-slipstreaming-v2-0/