$ sudo gem install ruby-ntlm

require 'ntlm/http'
http = Net::HTTP.new('www.example.com')
request = Net::HTTP::Get.new('/')
request.ntlm_auth('User', 'Domain', 'Password')
response = http.request(request)

require 'ntlm/imap'
imap = Net::IMAP.new('imap.example.com')
imap.authenticate('NTLM', 'User', 'Domain', 'Password')

require 'ntlm/smtp'
smtp = Net::SMTP.new('smtp.example.com')
smtp.start('localhost.localdomain', 'Domain\\User', 'Password', :ntlm) do |smtp|
  smtp.send_mail(mail_body, from_addr, to_addr)
end