> The NTP issue is rather specific and affected ntpd when you had > > server pool.ntp.org > server pool.ntp.org > server pool.ntp.org > > in your configuration. > > And some those mirrors I mentioned are affected by *deterministic* > reordering. They don't care if traffic hits the closest instance, > they want to spread the load (security.debian.org, for instance, is > difficult to serve from a single node from time to time). thanks for explaining that. > > and the nameserver examples you gave are all subject to rdns RTT > > sorting. > > If you follow Rule 9, you haven't got that many RTTs to sort by: Rule > 10 ensures that there is a single IP address you should use as long as > the service on it is reachable. Unless you cheat, deviate from Rule > 9, contact additional servers, and gather additional RTTs--but you > have to cheat to get that data. i don't know any recursive nameservers that follow RFC 3483 for authority server selection? (your example here was of authority nameservers.) > > and they have to use drastically low TTL's to prevent mobility from > > breaking their assumptions. and they have no way to cope with opendns > > or any other global or semi-coherent caching layer. and even when they > > use TTL=0 and happen to be talking to an rdns who shares topology with > > the stub, they're making an educated guess without knowing what kinds > > of wormholes the stub may have access to, whether VPN, private > > interconnects that don't show up in global BGP, or whatever. > > Well, if it's not a good idea, why are most large web sites served > this way? nobody ever got fired for buying $whatever. so: great marketing trumps any kind of engineering whether good or bad. > I suspect there is currently no better way to distribute initial > client requests than to play DNS tricks. since the web protocols support both permanent and temporary redirects, i've always preferred approaches like IBM's over approaches like akamai's. _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf