Test script to help diagnose erroneous NXDOMAIN responses from Ubiquiti networking gear

dns.rb

begin
  require "dnsruby"
rescue LoadError
  puts "gem install dnsruby"
end
require "yaml/store"

include Dnsruby

trap("SIGINT") { exit 1 }

nameservers = [
  { ip: "10.0.1.1", label: "local" },
  { ip: "193.229.0.40", label: "elisa" },
  { ip: "193.229.0.42", label: "elisa" },
  { ip: "8.8.8.8", label: "google" },
]

target = "static.squarespace.com"

store = YAML::Store.new "dns_results.yaml"

got_nx = false

until got_nx do
  run_start = Time.now
  results = nameservers.map do |ns, index|
    nxdomain = false
    res = Resolver.new(nameserver: [ns[:ip]])

    begin
      ret = res.query(target)
    rescue Dnsruby::NXDomain
      nxdomain = got_nx = true
    end

    puts "#{ns[:label]} (#{ns[:ip]}):\tnxdomain: #{nxdomain}"

    {
      ip: ns[:ip],
      label: ns[:label],
      results: ret.answer.map(&:to_s).join,
      nxdomain: nxdomain,
    }
  end

  store.transaction do
    store["results"] ||= []
    store["results"] << {
      run_start: run_start,
      run_end:  Time.now,
      results: results
    }
  end

  puts

  sleep 5
end