Notes for 9/26/2005
The 4-5 Section


Lecture notes

  • Hostnames map to IPs, so machines can use them.
  • DNS = Domain Name Service, does the mappings
  • /etc/hosts maps ips to hostnames
  • /etc/resolv.conf points to servers that can do so, if /etc/hosts doesn't have it.
  • Tools
    • host
    • Syntax is: host some.domain.name
    • Returns the IP associated with some.domain.name
    • Can also do reverse; ie: host 169.229.70.150 will return hal.rescomp.berkeley.edu
    • dig
    • Syntax is: dig some.domain.name or dig -x 169.229.70.150
    • Can also check MX records (ie the mailserver for a given domain) with dig some.domain.name mx
    • Server-side
    • /etc/named.conf
    • /etc/namedb/root.hints points to more authoritative DNS servers, if this server isn't authoratitive for a given domain.
    • /etc/namedb/* contains the IP->hostname (and vice-versa) mappings.