with MRI:
 
Socket.constants.grep /ip_/i
=> ["IP_MULTICAST_TTL", "IP_DEFAULT_MULTICAST_LOOP", "IP_HDRINCL", "IP_MULTICAST_LOOP", "IP_MAX_MEMBERSHIPS", "IP_TOS", "IP_ADD_MEMBERSHIP", "IP_TTL", "IP_DROP_MEMBERSHIP", "IP_MULTICAST_IF", "IP_DEFAULT_MULTICAST_TTL", "IP_OPTIONS"]
 
C:\dev\PIG-2.3>ir
IronRuby 1.0.0.0 on .NET 4.0.30319.1
Copyright (c) Microsoft Corporation. All rights reserved.
 

require 'socket'
=> true
Socket.constants.grep /ip_/i
=> [[