Re: Alternative to BGP-4 for multihoming?
Once the client's DNS request has worked its way over to the primary DNS for the distributed web-servers, 3DNS has each of the other 3DNS boxes (located adjacent to the other distributed servers) ping the *clients* primary DNS. 3DNS then returns the URL for the web-server whose 3DNS machine is 'closest' (fewest hops) to the clients DNS machine.
you may want to seriously reread the previous sender's message. the point is that in the modern post-2182 world, many of the client's nameservers are vastly net.distant from the client. psg.com nameserver = DNS.LIBRARY.UCLA.EDU psg.com nameserver = RAIN.PSG.COM psg.com nameserver = ARIZONA.EDU it is best common practice. randy
On Tue, 14 Mar 2000, Randy Bush wrote:
Once the client's DNS request has worked its way over to the primary DNS for the distributed web-servers, 3DNS has each of the other 3DNS boxes (located adjacent to the other distributed servers) ping the *clients* primary DNS. 3DNS then returns the URL for the web-server whose 3DNS machine is 'closest' (fewest hops) to the clients DNS machine.
you may want to seriously reread the previous sender's message. the point is that in the modern post-2182 world, many of the client's nameservers are vastly net.distant from the client.
psg.com nameserver = DNS.LIBRARY.UCLA.EDU psg.com nameserver = RAIN.PSG.COM psg.com nameserver = ARIZONA.EDU
it is best common practice.
Erm... no, not the nameservers for the domain the client is in, but the nameserver doing the DNS lookup. This will normally be a caching nameserver that may or may not be the same as the nameservers for the domain. In theory, it should be "close" to the client network wise for other reasons. Is it always? No. But it is a more reasonable metric. Not for best source, but for a reasonable source. Saying "the clients's primary DNS" is misleading. There is no way to know what the "primary" DNS server is for a zone, and there may not even be what is typically known as a primary.
On Tue, 14 Mar 2000, Marc Slemko wrote:
Saying "the clients's primary DNS" is misleading. There is no way to know what the "primary" DNS server is for a zone, and there may not even be what is typically known as a primary.
And to be done correctly, what "zone" is important? Would it be the server (primary/secondary/master/slave) authoritative for the reverse zone containing the client IP address? The domain name of the client found via reverse DNS? The caching proxy server in between (at the client end, or perhaps at the server end)? What if it's a UUNet resold modem to a client of iAmerica - what server gets used then? We know that UUNet's DNS servers are likely to not be located close (in net terms) to the client, and how do we know what DNS servers are being assigned to the client? Or what if my clients get assigned dns servers in 192.168.254/24? Sounds to me like it's not a valid geographic identifier. Pete -- Peter J. Templin, Jr., CCNA Systems and Networks Administrator On-Line Internet Services - URDirect.net A division of Global On-Line Computers 2414 Babcock Rd. Suite 106 templin@urdirect.net San Antonio, TX 78229 (210)692-9911
participants (3)
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Marc Slemko -
Pete Templin -
Randy Bush