A certain unnamed national provider of bagels has seen fit to limit free wifi during lunch hours. They do this based on MAC address. I never liked my MAC address anyways.


Update -- My previous code had two considerable bugs when I posted it. Caius Durling (http://caius.name/) made a considerable improvement with his own script. I've deleted my old code and just placed his here.

#!/usr/bin/env ruby
# 
# USAGE: Turn off wireless, run this, then turn it back on.
# ./random_mac.rb <nothing> # =>  random mac address
# ./random_mac.rb --reset # =>  original mac address

# Set this to your Original MAC Address
original_mac = ""

# Just a little warning
puts "Warning: You haven't set your original Mac Address in the script yet." if original_mac.empty?

# Generates a 2 digit code
def generate_pair
  a = rand(255).to_s(16)
  return (a.length < 2 ? generate_pair : a)
end

# Sets the mac address to the passed value
def set_mac_address( mac_addr )
  raise "MacAddressFormatError" if mac_addr.scan(/^(?:[\w\d]{2}\:){5}[\w\d]{2}$/).empty?
  puts "Old MAC address: #{`ifconfig en1 | grep ether`.match(/ether\s(.+)/)[1]}"
  `sudo ifconfig en1 ether #{mac_addr}`
  puts "New MAC address: #{`ifconfig en1 | grep ether`.match(/ether\s(.+)/)[1]}"
end



case ARGV.first
when "--reset"
  # Try to reset to old mac address
  if original_mac.empty?
    puts "ERROR - You need to set the old mac address in the script"
    exit(1)
  end
  puts "Resetting to old mac address"
  set_mac_address( original_mac )
  
when nil
  # Generate & set a random mac address
  random_mac = (0..5).map { |x| generate_pair }.join(":")
  set_mac_address( random_mac )
  
when "--help"
  # Show some help I guess
  puts [
    "USAGE: Turn off wireless, run this, then turn it back on.",
    "./random_mac.rb <nothing> # =>  random mac address",
    "./random_mac.rb --reset # =>  original mac address"
    ].join("\n")
  
else
  # Who knows?
  puts "Unknown Flag, try --help"
  exit(2)
end

Convert an integer to IP. I don't think you can do this with IPAddr, but I could be wrong

Edit, the original didn't work for low ranges.

And I was wrong about the IPAddr thing. I should have google'd better.

IPAddr.new(16909060, Socket::AF_INET).to_s

This was something I've searched for in the past but have yet to find. It's a super simple server and I'm sure there's a few bugs left in it, but the idea is simple and in my opinion, necessary. It's easy to send email from websites, but receiving it still seems dubious.

I've simply used Peter's(http://snippets.dzone.com/user/peter) ultra simplistic SMTP server and routed the email to a database table called "Emails" via ActiveRecord. It's running GServer so it should be able to handle a decent load. Like I mentioned earlier, it's probably still got some bugs, but it's a decent start.

require 'gserver'
require 'rubygems'  
require 'active_record'  
require 'yaml'
   
dbconfig = YAML::load_file(File.dirname(__FILE__) + '/config/database.yml')
ActiveRecord::Base.establish_connection(dbconfig['development']) 

class Email < ActiveRecord::Base   
end 

class SMTPServer < GServer
  def serve(io)
    @data_mode = false
    @email_message = ""
    puts "Connected"
    io.print "220 hello\r\n"
    loop do
      if IO.select([io], nil, nil, 0.1)
	      data = io.readpartial(4096)
	      puts ">>" + data
	      @email_message << data
	      ok, op = process_line(data)
	      break unless ok
	      puts "<<" + op
	      io.print op
      end
      break if io.closed?
    end
    db_insert(@email_message)
    io.print "221 bye\r\n"
    io.close
  end

  def process_line(line)
    if (@data_mode) && (line.chomp =~ /^\.$/)
      @data_mode = false
      return true, "220 OK\r\n"
    elsif @data_mode
      return true, ""
    elsif (line =~ /^(HELO|EHLO)/)
      return true, "220 and..?\r\n"
    elsif (line =~ /^QUIT/)
      return false, "bye\r\n"
    elsif (line =~ /^MAIL FROM\:/)
      return true, "220 OK\r\n"
    elsif (line =~ /^RCPT TO\:/)
      return true, "220 OK\r\n"
    elsif (line =~ /^DATA/)
      @data_mode = true
      return true, "354 Enter message, ending with \".\" on a line by itself\r\n"
    else
      return true, "500 ERROR\r\n"
    end
  end
  
  def db_insert(email)
    mail_from = (/^MAIL FROM\:<(.+)>.*$/).match(email)[1]
    rcpt_to = (/^RCPT TO\:<(.+)>.*$/).match(email)[1]
    subject = (/^Subject\: (.+)$/).match(email)[1]
    Email.create(:mail_from => mail_from, :rcpt_to => rcpt_to, :subject => subject, :email => email)
  end
  
end

a = SMTPServer.new(25)
a.start
a.join