RoundRobin DNS?
Len Conrad
LConrad at Go2France.com
Wed Jun 12 19:14:50 UTC 2002
> This is a first time I get a client big enough that needs this
> solution. Imagine a scenario, that you have a web server that can't go
> down. So you put it up at 2 different locations, say one in LA, other in
> NYC. So if say the ISP in LA goes down, NYC should theoretically start
> getting requests for webhits. That's what this client wants. So how is
> this done, I'm not sure this is done with DNS at all, although its a
> possibility. When I querry yahoo.com with nslookup, I get a few
> different ips. HOW IS THIS DONE? Can someone please point me in the
> right direction?
DNS can do blind load distribution by varying the physical order of records
in an RRset (eg, multiple ip's for a www.domain/IN/A query). But there is
in failover since visitors will be sent to an ip even if the web server is
down.
RAD Linkproof box (eBay, about $2k) can do intelligent load-balancing. The
www.domain.com donmain is delegated to the Linkproof which responds to A
queries (but is not a full DNS) and which passes out short TTL A records
based on the Linkproof's evaluation of the response www servers.
Also google for fezhead.
Len
www.menandmice.com/DNS-training : DNS Training
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