zlacker

NAT slipstreaming only works if your router allows protocols like SIP, FTP, WebRTC, and other such protocols that NAT breaks, luckily.

Unfortunately, I'm pretty sure that's all routers I've ever seen. You can protect yourself if you're willing to break web applications and applications built on web technology. Just disable all of the SIP ALGs in your router and you'll have the security of IPv6 on IPv4!