[ViPeR_930]

I recently enabled ipv6 on my router and noticed Youtube stops and buffers much more often. Is there any way I can force Youtube.com to use ipv4?

Netgear R7500V2 with DD-WRT v3.0-r30880M kongat (11/14/16)

[James2k]

There are a few ways, but mostly not very elegant as its generally against the main point IPv6 i.e. first protocol to be used (happy eyeballs) etc.

Probably the most elegant approach is you can prevent any DNS requests to YouTube domains from returning AAAA (IPv6) records, therefore making YouTube use IPv4 and your ISPs (normal?) gateway. In order to do this however you would need to setup an additional DNS resolver i.e. bind9 and use the option filter-aaaa-on-v4, you would then need to point any YouTube related domains that serve video to this DNS resolver rather than your normal DNS server(s). Its a similar technique used for Netflix, where by IPv6 tunnels are deemed as a proxy networks to bypass geo-restrictions and are now blocked outright, rather than disabling the tunnel, essentially you make Netflix think you only have IPv4 and hence IPv6 is not used. Same concept here, should work, needs to be implement at the router/DNS level though.

Other solutions are to change the IPv6 priority, but this is generally bad advice and against the purpose of IPv6 and doing it selectively isn't going to be possible, you'd be switching the protocol priority outright.

Alternatively you could null-route the IPv6 ranges of YouTube to force IPv4, but you may experience brief delays on requests and you'll probably have to go hunting for all the IPv6 ranges Google/YouTube is using (which might also change). In addition, Google/YouTube may other CDN or network services that arent't actually owned by them, so you may null-route innocent ranges for this purpose.

Ultimately, I'd query your buffering issue on YouTube with IPv6 with whoever is providing it, despite myself using a Hurricane Electric tunnel, YouTube performance is decent, considering the added latency. Actually in some cases depending on the setup, IPv6 may actually be faster than my IPv4 in some cases.