no_proxy?

# File lib/rubygems/request/connection_pools.rb, line 53
  def no_proxy? host, env_no_proxy
    host = host.downcase

    env_no_proxy.any? do |pattern|
      pattern = pattern.downcase

      host[-pattern.length, pattern.length] == pattern or
        (pattern.start_with? '.' and pattern[1..-1] == host)
    end
  end