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#!/usr/bin/ruby
require 'resolv'
require 'optparse'
require 'yaml'
NAGIOS_STATUS = { :OK => 0, :WARNING => 1, :CRITICAL => 2, :UNKNOWN => -1 };
@verbose = 0;
@additional_nameservers = []
def show_help(parser, code=0, io=STDOUT)
program_name = File.basename($0, '.*')
io.puts "Usage: #{program_name} [options] <domainname>"
io.puts parser.summarize
exit(code)
end
ARGV.options do |opts|
opts.on_tail("-h", "--help" , "Display this help screen") { show_help(opts) }
opts.on("-v", "--verbose" , String, "Be verbose") { @verbose += 1 }
opts.on("-a", "--add=HOST" , String, "Also check SOA on <nameserver>") { |val| @additional_nameservers << val }
opts.parse!
end
show_help(ARGV.options, 1, STDERR) if ARGV.length == 0
warnings = []
oks = []
dns = Resolv::DNS.new
ARGV.each{ |domain|
serial = []
nameservers = dns.getresources(domain, Resolv::DNS::Resource::IN::NS)
nameservernames = nameservers.collect{ |ns| ns.name.to_s }
nameservernames = nameservernames.concat @additional_nameservers
nameservernames.each{ |nameserver|
puts "Testing nameserver #{nameserver} for #{domain}" if @verbose > 0
arecords = dns.getresources(nameserver, Resolv::DNS::Resource::IN::A)
warnings << "Nameserver #{nameserver} for #{domain} has #{arecords.length} A records" if arecords.length != 1
arecords.each{ |a|
puts " Nameserver #{nameserver} is at #{a.address}" if @verbose > 0
resolver = Resolv::DNS.new({:nameserver => a.address.to_s})
begin
soas = resolver.getresources(domain, Resolv::DNS::Resource::IN::SOA)
rescue SystemCallError => e
warnings << "Could not resolve #{domain} on #{nameserver}: #{e.message}"
else
warnings << "Nameserver #{nameserver} for #{domain} returns #{soas.length} SOAs" if soas.length != 1
soas.each{ |soa|
puts " Nameserver #{nameserver} returns serial #{soa.serial} for #{domain}" if @verbose > 0
serial << soa.serial unless serial.include? soa.serial
}
end
resolver.close
}
}
case serial.length
when 0
warnings << "Found no serials for #{domain}"
when 1
oks << "#{domain} is at #{serial.first}"
else
warnings << "Nameservers disagree on serials for #{domain}: found #{serial.join(', ')}" if serial.length != 1
end
}
dns.close
if warnings.length > 0
puts warnings.join('; ')
exit NAGIOS_STATUS[:WARNING]
else
puts oks.join('; ')
exit NAGIOS_STATUS[:OK]
end
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