Architecture of DNS

1
Architecture of DNS

• CS 718
• Activity 4
• Submitted by
• Parag Abhyankar 08305017
• Anup S. Kunte 08305302

2
The Domain Name System

• The domain name system is usually used to
  translate a host name into an IP address .
• Domain names comprise a hierarchy so that names
  are unique, yet easy to remember.

3
DNS Servers

• Servers handle requests for their domain
  directly.
• Servers handle requests for other domains by
  contacting remote DNS server(s).
• The server finds a nameserver for the target
  domain.
• The server asks the nameserver to provide the
  host name to IP translation.
• Servers cache external mappings.

4
DNS Infrastructure

• Host at cis.poly.edu wants IP address for
  gaia.cs.umass.edu
• Infrastructure
• Client resolver
• Local DNS server
• Authoritative DNS Server
• Root DNS Server
• Top-Level Domain DNS Server

5
Iterated query
root DNS server

• iterated query
• contacted server replies with name of server to
  contact
• I dont know this name, but ask this server

6
Recursive queries

• recursive query
• puts burden of name resolution on contacted name
  server
• heavy load?

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Subsequent Lookup Operations
root DNS server

• DNS responses are cached
• Quick response for repeated translations
• DNS negative queries are cached
• Dont have to repeat past mistakes

TLD DNS server
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3
1
4
authoritative DNS server dns.cs.umass.edu
requesting host cis.poly.edu
gaia.cs.umass.edu
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Comment on DNS Architecture

• Architecture of DNS can be considered as a mix of
  client-server and peer-peer.
• Interaction between DNS server and client
  requesting name resolution is clearly
  client-server architecture.
• Interaction between any two DNS servers is p2p
  architecture.