But do the commonly-used operating systems support adding hundreds or thousands of addresses to an interface, and what would the performance implications be?
Jeff Ollie
Last time I checked, and this may have changed, the limit in Linux was around 4096. In practice though, you also have to consider the physical limitations of the server itself. The biggest bang for the buck in dense hosting environments seems to be running about 1000 sites per box, with a few boxes dedicated to your heavy hitters with 100 or less ea. Until we start seeing IPv6-only hosting though, I suspect that we will see IPv6 address mirror the configuration of the IP assignments. Sites with dedicated IPs will have dedicated IPv6, sites with shared IP will have shared IPv6, if only to maintain sanity. If you're trying to make the case for IPv6 to hosting companies, you're barking up the wrong tree. IP address just became a scarce commodity, instead of providing you with a free IP address, the can now charge $100 a mo for one. They know darn well that it will take a while for every user to have IPv6 from their SP and that if you want to run a site you'll need access to the "legacy" IP Internet to reach your customers. On the bright side, this will encourage the market to adopt IPv6 because they can't afford IP. Hopefully ARIN adopts a policy of decommissioning IP space as they reclaim it to prevent people from receiving new allocations as people begin to go IPv6-only, otherwise we'll be stuck with two Internets for a very long time. -- Ray Soucy Communications Specialist +1 (207) 561-3526 Communications and Network Services University of Maine System http://www.maine.edu/