Csvunl resolves robotcswashingtonedu 111 9 112613

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Unformatted text preview: DNS Zones •  A zone is a con8guous por8on of the namespace Delega8on A zone 106 DNS Zones (2) •  Zones are the basis for distribu8on –  EDU Registrar administers .edu –  UW administers washington.edu –  CS&E administers cs.washington.edu •  Each zone has a nameserver to contact for informa8on about it –  Zone must include contacts for delega8ons, e.g., .edu knows nameserver for washington.edu 107 7 11/26/13 DNS Resource Records •  A zone is comprised of DNS resource records that give informa8on for its domain names Type Meaning SOA Start of authority, has key zone parameters A IPv4 address of a host AAAA (“quad A”) IPv6 address of a host CNAME Canonical name for an alias MX Mail exchanger for the domain NS Nameserver of domain or delegated subdomain 108 DNS Resource Records (2) Name server IP addresses of computers Mail gateways 109 8 11/26/13 DNS Resolu8on •  DNS protocol lets a host resolve any host name (domain) to IP address •  If unknown, can start with the root nameserver and work down zones •  Let’s see an example first … 110 DNS Resolu8on (2) •  flits.cs.vu.nl resolves robot.cs.washington.edu 111 9 11/26/13 Itera8ve vs. Recursive Queries •  Recursive query –  Nameserver completes resolu8on and returns the final answer –  E.g., flits à༎ local nameserver •  Itera8ve query –  Nameserver returns the answer or who to contact next for the answer –  E.g., local nameserver à༎ all others 112 Itera8ve vs. Recursive Queries (2) •  Recursive query –  Lets server offload client burden (simple reso...
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This document was uploaded on 04/04/2014.

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