Martin, Yes, the issues with an unconditional "prefer IPv6" approach have been noted, and operating systems of the vintages you mention certainly deserved criticism. In fact this has been a major focus of IPv6 operational discussions, and lies behind things like the DNS whitelisting method, the happy-eyeballs work, and my own RFC 6343. Old news; unfortunately it means you need new o/s versions. Disabling 6to4 and Teredo unless they are known to be working well is a good start, however. Regards Brian Carpenter On 2012-02-24 05:51, Martin Rex wrote: > Bob Hinden wrote: >> Martin Rex wrote: >>> With a fully backwards compatible transparent addressing scheme, >>> a much larger fraction of the nodes would have switched to actively >>> use IPv6 many years ago. >> Right, just like they could have deployed dual stack many years ago too. > > Just two days ago I had an extremeley disappointing experience with IPv6. > Windows XP 64-bit (aka Win2003sp2) on a local network with a private > DNS universe, IPv4 only network, Windows IPv6 protocol stack installed > but IPv6 active only on the two virtual network interfaces of VMware. > > Somehow the DNS servers configured in the network settings had performed > only a partial zone reload and were replying only to some queries, > failing some DNS queries with server failure or timeout, > and one DNS zone had become completely invisible. > > I noticed the problem suddenly during work because every new connection > took ~16 seconds delay to complete. Wondering what was wrong, I started > wireshark. > > I saw Windows2003 send out 23 DNS lookups for AAAA records for the > requested hostname over the course of 16 seconds (some of which returned > server failure, some of which failed with no such name), > until Windows 2003 finally decided to also try a DNS A query--which got > immediately successfully answered and the connection was established. > The delay affected each and every connection attempt, even when contacting > the same host repeatedly (although there is a DNScache service running...). > > Disabling IPv6 on all network adapters did not stop this Windows AAAA frenzy, > I had to actually uninstall the IPv6 protocol stack (an action which > immediately kills *ALL* network connectivity of the machine and requires > a reboot to recover...) for this AAAA nonsense to end. > > During the past few years I had two similar encounters with sudden severe > connectivity problems on a Windows XP and a Linux installation, and > both times, the problem disappeared when I disabled IPv6. > > It is also significantly easier to configure the firewall for IPv4-only... > > -Martin > _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf