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DNS DNS

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DNS DNS Powered By Docstoc
					                           DNS
• Domain Name System
  – name servers
  – Translates FDQN to IP address
     • List of fully qualified domain names (FDQN) and
       their IP addresses,
     • FDQN has three or more segments
        – first segment is host the rest of the segments are for the
          network in which the host is located
             » www.ivc.edu
             » www.ivc.cc.ca.us
• Manual Translation
  – /etc/hosts
                     Domains
• Internet is composed of many domains
• Each domain needs a DNS server to keep track
  of the FDQN and IP address on it’s network
• The section that the DNS is responsible for is
  called a zone
• One domain may corresponded to a domain,
  many zones may be within a domain each with
  its on name server
  – i.e. .gov .com .edu .net
• DNS operation:
  – Client request connection to remote host by
    entering a FDQN, the DNS server responds
    with the corresponding IP address, the client
    then connects to remote host by IP address
• DNS Client
  – The name of the DNS servers that service a
    host network are kept in /etc/resolv.conf
    • Usually specified when setting up the network
      connection.
                   BIND
• Berkeley Internet Name Domain
  – Developed at Cal. Berkeley
  – Maintained by Internet Software Consortium
    (ISC) www.isc.org
• Local documentation:
  – /usr/share/doc/bind-9.4..0
  – /usr/share/doc/bind-9.4.0/arm/Bv9ARM.html
• Documentation and tools
  – www.dns.net/dnsrd
             Servers and Tools
• BIND DNS software
  – name server daemon ( named )
      • rndc tool can be used to manage
  – sample configuration files
  – resolver libraries
• Tools
  – dig and nslookup test basic operation of named ( DNS )
  – named-checkconfig
     • Checks syntax of DNS configuration file ( named.conf )
  – named-checkzone
     • Checks syntax of zone file
  – GUI system-config-bind
        Starting and Stopping
• service named start
  – stop, restart, status
• chkconfig named on
               Configuration
• configuration file
  – named.conf
• zone files
  – defined in named.conf
  – IP to FDQN association
  – Types
     • Master, Slave, Forward, IN-ADDR.ARPA, Hint
• cache file
              Server Types
•   Master Server
•   Slave Server
•   Forwarder Server
•   Caching only server
•   Stealth server
        Location of BIND files
/var/named/chroot
  – chroot directory sets up a chroot jail, a virtual
    root directory for users of the DNS service
     • documentation www.tldp.org
• Configuration Files
  – /var/named/chroot/etc/named.conf
  – /var/named/chroot/var/named/*
     • zones
• named.conf
   – consists of BIND statements with attached
     blocks within which specific options are listed
      • Reference Page 836 and 837
• Zone files
   – hold domain name information about hosts in
     resource records
     • takes up one line but can be extended by using
       parentheses to use several lines usually the case
       with a SOA record
• name [<ttl>] [<class>] <type> <rdata> [<comment>]
system-config-bind

				
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posted:11/15/2011
language:English
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