nanog mailing list archives
Re: lists of DNS servers by region.
From: Valdis.Kletnieks () vt edu
Date: Thu, 12 Dec 2002 15:09:36 -0500
On Thu, 12 Dec 2002 14:42:08 EST, Haesu said:
Many DNS "load balancing" solutions will return the address of the web server closest to the _query source_. This means these systems work best when your recursive DNS servers are topologically closest to your users.Correct me if I am wrong.. But.. I don't think multiple 'A' record load balancing will return the IP address of the web server that is closest to the _query_source_. If this is true, then Akamai has reinvented the wheel with their near-by DNS setup on *.g.akamai.net entries.
Akamai doesn't use the usual round-robin. They do OTHER magic. Some solutions use a special magic DNS backend that will launch a PING or other RTT detector from the multiple service locations, and then return the location with the lowest RTT. Of course, this means you're measuring the RTT from the servers to the user's DNS server - if they're using a DNS server that's a long way away network-wise, this can produce odd results. The problem is that the backend doesn't know the source of the original query, they only know the IP address of the DNS server that's doing the recursion. -- Valdis Kletnieks Computer Systems Senior Engineer Virginia Tech
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Current thread:
- lists of DNS servers by region. Tatsuya Kawasaki (Dec 11)
- Re: lists of DNS servers by region. Stephen Sprunk (Dec 11)
- Re: lists of DNS servers by region. Brian (Dec 12)
- <Possible follow-ups>
- Re: lists of DNS servers by region. Tatsuya Kawasaki (Dec 12)
- Re: lists of DNS servers by region. Robert E. Seastrom (Dec 12)
- Re: lists of DNS servers by region. Pascal Gloor (Dec 12)
- Re: lists of DNS servers by region. Haesu (Dec 12)
- Re: lists of DNS servers by region. Valdis . Kletnieks (Dec 12)
- Re: lists of DNS servers by region. Haesu (Dec 12)
- Re: lists of DNS servers by region. Valdis . Kletnieks (Dec 12)