Re: RIPE our of IPv4

[Brandon Martin <lists.nanog () monmotha net>]

On 11/30/19 8:55 PM, Valdis Klētnieks wrote:
> > User apps prefer IPv6, Netflix stops, users complain
> And fallback to IPv4 fails to happen, why, exactly?

Inability to signal application-level failure on IPv6 and that fallback to IPv4 would succeed.

Netflix definitely exhibits this.  I've also noticed that a lot of Cloudflare-hosted apps/sites block AS6939 outright 
which mostly only affects IPv6 as they don't actually originate much end-user-facing IPv4 space.  The result is an 
HTTP/403 which most browsers do not interpret as a response that could be remedied by "happy eyeballs" type behavior.  
Whether banning an entire ASN like that in precisely a situation where this kind of thing is likely to occur is a good 
practice or not is left as an exercise to the reader.
-- 
Brandon Martin