bt # host
Usage: host [-aCdlriTwv] [-c class] [-N ndots] [-t type] [-W time] [-R number] hostname [server]

  • a is equivalent to -v -t *
  • c specifies query class for non-IN data
  • C compares SOA records on authoritative nameservers
  • d is equivalent to -v
  • l lists all hosts in a domain, using AXFR
  • i IP6.INT reverse lookups
  • N changes the number of dots allowed before root lookup is done
  • r disables recursive processing
  • R specifies number of retries for UDP packets
  • t specifies the query type
  • T enables TCP/IP mode
  • v enables verbose output
  • w specifies to wait forever for a reply
  • W specifies how long to wait for a reply
  • 4 use IPv4 query transport only
  • 6 use IPv6 query transport only