# See #NS

# = Name Server Record (NS)
#
# Defined in RFC 1035. NS RRs appear in two places. Within the zone file, in
# which case they are authoritative records for the zone's name servers. At the
# point of delegation for either a subdomain of the zone or in the zone's
# parent. Thus the zone example.com's parent zone (.com) will contain
# non-authoritative NS RRs for the zone example.com at its point of delegation
# and subdomain.example.com will have non-authoritative NS RSS in the zone
# example.com at its point of delegation. NS RRs at the point of delegation are
# never authoritative only NS RRs for the zone are regarded as authoritative.
# While this may look a fairly trivial point, is has important implications for
# DNSSEC.
#
# NS RRs are required because DNS queries respond with an authority section
# listing all the authoritative name servers, for sub-domains or queries to the
# zones parent where they are required to allow referral to take place.
#
# Obtained from http://www.zytrax.com/books/dns/ch8/ns.html
#
class NS < Record
  validates :name, :hostname => {:allow_underscore => true}
  validates :content, :presence => true, :hostname => true, :inclusion => {:in => Settings.ns}

  def to_label; "#{content}" end
end

Ns = NS