Am Wednesday 02 February 2011 schrieben Sie: > On Wednesday 2011-02-02 00:00, Guido Winkelmann wrote: > >On Tuesday 01 February 2011 22:38:49 you wrote: > >>that each VPS can only use the IP and MAC addresses > >>assigned to them. > >>With IPv6, does anyone have any experience on how to do this? I > >>know we can use ip6tables, but isn't there some trickery with NDP > >>(Which replaces ARP)? > > > >There shouldn't be, just as long as you only filter on the source > >address of outgoing packets, and not on the destination of incoming > >ones. The NDP request packets go to weird multicast addresses > > That "weird multicast address" is just broadcast so to speak, there is > nothing weird about it. Well, from what I could gather in wireshark, it's a bunch of different dst addresses that are used for that, and which one is used appears to depend on the address being queried... > >Answer packets for NDP always have a valid IPv6 address from the answering > >host as their source address. Also, they're IPv6 packets like any other > >and not a separate protocol as with ARP+IPv4. > > > >Note that hosts using IPv6 will usually have at least two autoconfigured > >addresses > > Can you back up this statement? Well, as soon as you enable IPv6 on a host, all of its interface will generally immediately be assigned an autoconfigured link-local address calcaluted from the MAC address. As soon the host receives a router advertisement on one of its interfaces, it will auto-configure an additional address from the advertised prefix and its MAC. Of course, if you don't have any IPv6 routers on the local net, or if they don't send router advertisements, then the second autoconfigured address will not exist, but then, if there is no IPv6 router, then saying the host is "using IPv6" is a bit far fetched, and having an IPv6 router on the local network that does not send any router advertisements is, as far as I can tell, a rare corner case. Guido -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
