I've heard that for very large service providers, it is possible to run out of 1918's. IIRC Comcast did a presentation where they figured they needed 100 millio

I've heard that for very large service providers, it is possible to run out of 1918's. IIRC Comcast did a presentation where they figured they needed 100 million IP addresses for a nation wide rollout of their triple play service. They appear to be highly motivated to use 6, as the alternative - partitioned 1918's would be a nightmare. I agree, though, that exposing your services to the Internet via both 6 and 4 and leaving the backend internal data center at 4 is probably the way to go for the next decade or so. Heck - we are still running DecNet on production servers.