Ping an email address to see if it exists. This script resolves MX records to find the SMTP server responsible for delivering mail to the address, connects to it, and starts to send a message to the address. It disconnects before the message is sent.

email-ping.rb

#!/usr/bin/env ruby
#
# = Email Ping
#
# Check to see if an email address exists by looking up MX records and connecting
# to the address's home SMTP server. It then starts to send a message to the address
# but quits before the message is actually sent.

require 'resolv'
require 'net/smtp'

address = ARGV[0].chomp
domain = address.split('@').last
dns = Resolv::DNS.new

puts "Resolving MX records for #{domain}..."
mx_records = dns.getresources domain, Resolv::DNS::Resource::IN::MX
mx_server  = mx_records.first.exchange.to_s
puts "Connecting to #{mx_server}..."

Net::SMTP.start mx_server, 25 do |smtp|
  smtp.helo "loldomain.com"
  smtp.mailfrom "[email protected]"

  puts "Pinging #{address}..."

  puts "-" * 50

  begin
    smtp.rcptto address
    puts "Address probably exists."
  rescue Net::SMTPFatalError => err
    puts "Address probably doesn't exist."
  end
end

# vim: set ft=ruby ts=2 sw=2 :