require 'net/smtp'
require 'rubygems'
require 'tlsmail' # gem install tlsmail

hosts = ['abc.com', 'defg.com']

mail_auth = {
  :server => 'xxxx',
  :port => 25,
  :username => 'xxxx',
  :password => 'xxxx'
}

ping_cmd = '/sbin/ping'

recips = ['notify@this_email.com']

for host in hosts
  `#{ping_cmd} -c 1 #{host}` =~ /time=([0-9\.]+)/

  if $1
    File.open("pinger-#{host}", 'a') {|f| f.write "#{Time.now}: #{$1} ms\n"}
  else
    File.open("pinger-#{host}", 'a') {|f| f.write "#{Time.now}: Unreachable\n"}

    headers = ['From: pinger <pinger@xxx.com>',
      "Subject: [pinger] #{host} is unreachable"]

    message = "#{host} unreachable, yikes."

    Net::SMTP.enable_tls(OpenSSL::SSL::VERIFY_NONE)
    Net::SMTP.start(mail_auth[:server], mail_auth[:port], '', mail_auth[:username], mail_auth[:password], :login) do |smtp|
      smtp.send_message "#{headers.join("\n")}\n\n#{message}", 'pinger@xxx.com', recips
    end

  end
end