On: Why ALIAS-type DNS Records Break The Internet

[JoachimSchipper]

I agree that this would work decently well if you could actually specify a 60-second TTL; but there are quite a few DNS resolvers that cache responses for at least a day, and there's not a whole lot you can do to change that. (This makes some sense - re-resolving all the time doesn't help performance!)

[imbriaco → JoachimSchipper]

"Quite a few" is actually a very very small percentage these days.

If your ISP is disregarding TTL, you're just as bad off with CNAMEs pointing at a third party as you are with the ALIAS-type record.

[donavanm → JoachimSchipper]

Yeah, around 1% of resolvers seriously disregarding TTLs is what Ive seen. But if thats the argument theres absolutely no difference in cache lifetime of a single A backed by an ALIAS resolution and the typical A + CNAME. In either case all of the records should be cached for the broken resolvers lifetime. To counter that you do dns cache busting with prepended GUID labels or the like. Which totally breaks caching anyways.