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#! /usr/bin/env ruby
# --
# Copyright 2007 Nominet UK
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ++
# = NAME
#
# check_zone - Check a DNS zone for errors
#
# = SYNOPSIS
#
# check_zone [ -r ] <domain>
#
# = DESCRIPTION
#
# Checks a DNS zone for errors. Current checks are:
#
# * Checks that all A records have corresponding PTR records.
#
# * Checks that hosts listed in NS, MX, and CNAME records have
# A records.
#
# = OPTIONS
#
# * -r Perform a recursive check on subdomains.
#
# = AUTHOR
#
# Michael Fuhr <mike@fuhr.org>
# (Ruby version AlexD, Nominet UK)
#
def fatal_error(message)
puts message
exit(-1)
end
unless (1..2).include?(ARGV.length)
fatal_error("Usage: #{$0} domain [ class ]")
end
require 'dnsruby'
require 'getoptLong'
def check_domain(args)
domain = args[0]
klass = args[1] || 'IN'
puts "----------------------------------------------------------------------"
puts "#{domain} (class #{klass}\n"
puts "----------------------------------------------------------------------"
resolver = Dnsruby::Resolver.new
resolver.retry_times = 2
nspack = begin
resolver.query(domain, 'NS', klass)
rescue Exception => e
print "Couldn't find nameservers for #{domain}: #{e}\n"
return
end
print "nameservers (will request zone from first available):\n"
ns_answers = nspack.answer.select {|r| r.type == 'NS' }
ns_domain_names = ns_answers.map(&:domainname)
ns_domain_names.each { |name| puts "\t#{name}" }
puts ''
resolver.nameserver = ns_domain_names
zt = Dnsruby::ZoneTransfer.new
zt.server = ns_domain_names
zone = zt.transfer(domain) # , klass)
unless zone
fatal_error("Zone transfer failed: #{resolver.errorstring}")
end
puts "checking PTR records"
check_ptr(domain, klass, zone)
puts "\nchecking NS records"
check_ns(domain, klass, zone)
puts "\nchecking MX records"
check_mx(domain, klass, zone)
puts "\nchecking CNAME records"
check_cname(domain, klass, zone)
print "\n"
if @recurse
puts 'checking subdomains'
subdomains = Hash.new
# foreach (grep { $_->type eq 'NS' and $_->name ne $domain } @zone) {
zone.select { |i| i.type == 'NS' && i.name != domain }.each do |z|
subdomains[z.name] = 1
end
# foreach (sort keys %subdomains) {
subdomains.keys.sort.each do |k|
check_domain([k, klass])
end
end
end
def check_ptr(domain, klass, zone)
resolver = Dnsruby::Resolver.new
# foreach $rr (grep { $_->type eq 'A' } @zone) {
zone.select { |z| z.type == 'A' }.each do |rr|
host = rr.name
addr = rr.address
ans = nil
begin
ans = resolver.query(addr.to_s, 'A') #, klass)
puts "\t#{host} (#{addr}) has no PTR record" if ans.header.ancount < 1
rescue Dnsruby::NXDomain
puts "\t#{host} (#{addr}) returns NXDomain"
end
end
end
def check_ns(domain, klass, zone)
resolver = Dnsruby::Resolver.new
# foreach $rr (grep { $_->type eq "NS" } @zone) {
zone.select { |z| z.type == 'NS' }.each do |rr|
ans = resolver.query(rr.nsdname, 'A', klass)
puts "\t", rr.nsdname, ' has no A record' if (ans.header.ancount < 1)
end
end
def check_mx(domain, klass, zone)
resolver = Dnsruby::Resolver.new
# foreach $rr (grep { $_->type eq "MX" } @zone) {
zone.select { |z| z.type == 'MX' }.each do |rr|
ans = resolver.query(rr.exchange, 'A', klass)
print "\t", rr.exchange, " has no A record\n" if (ans.header.ancount < 1)
end
end
def check_cname(domain, klass, zone)
resolver = Dnsruby::Resolver.new
# foreach $rr (grep { $_->type eq "CNAME" } @zone)
zone.select { |z| z.type == 'CNAME' }.each do |rr|
ans = resolver.query(rr.cname, 'A', klass)
print "\t", rr.cname, " has no A record\n" if (ans.header.ancount < 1)
end
end
def main
opts = GetoptLong.new(['-r', GetoptLong::NO_ARGUMENT])
@recurse = false
opts.each do |opt, arg|
case opt
when '-r'
@recurse = true
end
end
check_domain(ARGV)
end
main
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