mdns-repeater is a Multicast DNS repeater for Linux. Multicast DNS uses the 224.0.0.51 address, which is "administratively scoped" and does not leave the subnet.
mdns-repeater provides a "keep it simple, stupid" solution to discovering mDNS services across subnets, and is primarily intended for router distributions and software firewalls.
Since the mDNS protocol sends the AA records in the packet itself, the repeater does not need to forge the source address. Instead, the source address is of the interface that repeats the packet.
mdns-repeater only requires the interface names and it will do the rest. For example, the dd-wrt standard installation defines br0 for the wireless interface and vlan1 as the WAN interface, I would use:
mdns-repeater br0 vlan1
You can also specify the -f flag for debugging, which prints packets as they are received.
You are free to modify the code to repeat whatever traffic you require, as long as you abide by the software license.
Copyright (C) 2011 Darell Tan
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.