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Re: large organization nameservers sending icmp packets to dns servers.
On Mon, 06 Aug 2007 11:53:15 EDT, Drew Weaver said: > Is it a fairly normal practice for large companies such as Yahoo! And > Mozilla to send icmp/ping packets to DNS servers? If so, why? Sounds like one of the global-scale load balancers - when you do a (presumably) recursive DNS lookup of one of their hosts, they'll ping the nameserver from several locations and see which one gets an answer the fastest. Yes, it's a semi-borkken strategy, because it assumes that: 1) ICMP is handled at the same rate as TCP/UDP packets in all the routers involved (so there's no danger of declaring a path "slow" when it really isn't, just becase a router slow-pathed ICMP). 2) That the actual requester of service is reasonably near net-wise to the server handling the end-user's recursive DNS lookup.