John, I agree that your draft is clever. But I think it's really stretching DNS way beyond what it was designed for and it might be time to look at a different approach. To paraphrase the old saying, when all you have is DNS, every problem looks like a lookup.
I agree that it's sort of an odd way to use the DNS. But the DNS has a huge advantage over hypothetical alternatives -- the DNS exists, and the alternatives don't. Consider all of the cruddy middleware that has special cases to let DNS traffic through, the extreme efficiency of DNS queries, and the universal availability of DNS caches. Before I switched to an alternative I would want to make really sure that when I was done I would end up with something that actually worked better.
I'm not wedded to the CNAME hack. Maybe some sort of version number that would give the client a hint to go back and start over would work better. Or quite possibly the CNAMEs are adequate to keep clients no more than a few minutes out of sync with the server, which is all BLs expect now.
Regards, John Levine, jo...@taugh.com, Taughannock Networks, Trumansburg NY "I dropped the toothpaste", said Tom, crestfallenly. PS: While you're at it, SMTP needs to be replaced, too.
