From: Glen Holcomb <damnbigman@...>
Date: 2008-09-19T05:53:33+09:00
Subject: Re: Reliable ping method from Windows?

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On Thu, Sep 18, 2008 at 2:09 PM, Glen Holcomb <damnbigman@gmail.com> wrote:

> Is there a reliable "Ruby" method for pinging/checking whether hosts are
> up?
>
> I have been using Net::PingExternal as I'm pinging Windows machines and not
> all of them have port 7 open.  However when I try to check 900 or so
> machines I get a SocketError after a while.  It complains that there is no
> such service echo/tcp.  When I try similar code in irb I get the socket
> error after a few minutes then if I try the loop again I get the socket
> error immediately.
>
> I've tried a generic ICMP packet but that doesn't work under Windows with
> the standard Ruby build and I don't have the tools/time to build it my self
> under Windows.
>
> --
> "Hey brother Christian with your high and mighty errand, Your actions speak
> so loud, I can't hear a word you're saying."
>
> -Greg Graffin (Bad Religion)
>

Here is the full method if anyone wants more context:

  # Lets find MAC addresses for the machines in the list
  def find_macs
    # This technique will only give MAC addresses for the machines on our
subnet.
    #    However since those are the only ones we can wake it doesn't really
matter.
    #    It is nasty slow and a better way should be found some day.

    DB[:computers].each do |computer|
      begin
        Net::PingExternal.new(computer[:name]).ping
      rescue SocketError => exception
        next
      end
    end

    arp_table = `arp -a`.split("\n")[2..-1]

    arp_table.each do |address|
      full_name = Socket.gethostbyname(address.split(' ')[0])

      comp = Computer.find :name => full_name.split('.')[0]
      comp.mac = address.split(' ')[1].gsub!('-', ':')
      comp.save
    end
    close()
  end # find_macs

-- 
"Hey brother Christian with your high and mighty errand, Your actions speak
so loud, I can't hear a word you're saying."

-Greg Graffin (Bad Religion)

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