Re:What happens when you update your DNS
by toast0 on Monday June 22, 2020 @10:49PM
(#23609460)
> Which of those hosts should I open a TCP connection to to begin speaking TLS/ALPN/HTTP2? The standard doesn't say. I would like a standard that says what to do.
Well, there was an RFC (found it, RFC 3484) that told you to pick the one closest to your network (which wouldn't make a difference in this case, unless you were in say 13.225.214.0/27 or so). But that's not actually helpful, because given two destination IPs, one in the same /8 as me, and one not, I don't have any information that would help me determine which is a better choice.
From experience, most browsers will try a couple IPs before showing an error message, but that's not standard. If you have a fancy authoritative server, a lot of traffic, and a bunch of server IPs, you can get OK balancing by telling some clients some IPs and some clients other IPs; but it depends on having enough diversity in recursive servers; if all of your users are coming from one mobile ISP, chances are you won't get a lot of balancing.
(And I'm sure you already know all this :)
Better to have clients with a bit of intelligence. :)
Well, there was an RFC (found it, RFC 3484) that told you to pick the one closest to your network (which wouldn't make a difference in this case, unless you were in say 13.225.214.0/27 or so). But that's not actually helpful, because given two destination IPs, one in the same /8 as me, and one not, I don't have any information that would help me determine which is a better choice.
From experience, most browsers will try a couple IPs before showing an error message, but that's not standard. If you have a fancy authoritative server, a lot of traffic, and a bunch of server IPs, you can get OK balancing by telling some clients some IPs and some clients other IPs; but it depends on having enough diversity in recursive servers; if all of your users are coming from one mobile ISP, chances are you won't get a lot of balancing.
(And I'm sure you already know all this :)
Better to have clients with a bit of intelligence. :)