Pavel, I concur with your description of the problem. do you have a proposal for how it can be solved?
Best regards, Ole On Apr 19, 2012, at 23:32 , Pavel Šimerda wrote: > Hello, > > I'm starting my work on linux NetworkManager. I've been following > several bugreports during the recent months that all lead to problems > with maintaining the list of recursive nameservers. > > I've already spent quite some time analyzing RDNSS problems and I came > to a conclusion that the problem actually lives in the RFC itself. > > Please look at section 5.1. in RFC 6106. It states: > > MaxRtrAdvInterval <= Lifetime <= 2*MaxRtrAdvInterval > > Considering MaxRtrAdvInterval the maximum time between RAs, setting > Lifetime to MaxRtrAdvInterval IMO constitutes a race condition. > Moreover, any Lifetime in this interval can timeout with just one or two > lost RAs. > > This makes RA-based IPv6-only networks drop RDNSS regularly. In many > implementations IPv6 and IPv4 are bound together so that if one of them > fails, the whole link is restarted. This is also the case in > NetworkManager. > > In the current situation, it's not advisable to use RFC 6106 in > production because it can cause problems even to IPv4 applications. > > In the real world, radvd uses Lifetime=MaxRtrAdvInterval by default and > NetworkManager internally adds 10s to the lifetime, that only helps to > avoid the race condition but not lost packets that are common on > wireless networks. > > I appreciate any help to get this right both in the standards and in the > software. > > Cheers, > > Pavel Šimerda > > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > ipv6@ietf.org > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
