said by InvalidError:said by 34764170:Another area that will benefit greatly from IPv6 is VoIP. SIP is a total pain with NAT.
The main reason for the pain is simply the requirement to keep an inbound port open on the accidental firewall created by NAT's IP:port S:D connection tracking: can't forward inbound until you know who to forward the traffic to.
You would run into many of the same problems with a basic IPv6 firewall that denies inbound by default much the same way NAT routers do.
An additional portion of this problem is that there still isn't a very well defined port management system for IPV6 firewalls.
With V4 we have NAT-PMP and UPnP (gross) to handle this. V6 still doesn't really have a counterpart to tell the firewall to open ports as needed by opening/closing applications.
The port problem is compounded by address randomization on V6 networks by default in most OS's in SLAAC environments. DHCPv6 can solve this to some extent in that you can configure your router manually to always give your computer a specific address and then manually open ports needed but that's a pretty lousy solution compared to the relatively transparent operating of a NAT with PMP/UPnP support.
This is one area where Apple can show some real leadership - updating NAT-PMP to work well with IPv6 and really push it as a standard. Alas, Apple seems to care about 0% about IPv6, as evidenced by their V6 stack on OS X (happy eyeballs always on and can't be disabled) and their routers (PPPoE IPv6 completely unsupported).
Sigh.