HOSTLIST.each do |host|
  begin
    Net::SSH.start(host, USER, :password => PASSWORD, :timeout => TIMEOUT) do |ssh|
      output = ssh.exec!('ls')
      puts output
    end
  rescue Timeout::Error
   puts "+++++++ Timed out"
  rescue Errno::EHOSTUNREACH
   puts "+++++++ Host unreachable"
  rescue Errno::ECONNREFUSED
   puts "+++++++ Connection refused"
  rescue Net::SSH::AuthenticationFailed
   puts "+++++++ Authentification failure "
  end
end