Cast from a different network

If the home network has been split into several sub-networks (dedicated network for: guests, IoT equipment, 3rd-party devices, …) usually to improve security, it could lead to the Chromecast devices not being discovered anymore.

Chromecast (or in my case the FreeBox POP) is detected by performing an mdsn query, this type of query doesn’t cross network boundary (multicast packet TTL is set to 1).

Two possible solutions are:

  • if the firewall permit it, rewrite the TTL field to increase it’s value an allow it to cross the network
  • the packet can be repeated on other interfaces using a program such as mdns-repeater

Configuration example using mdns-repeater to repeat mdns packet between interfaces net0 and net1

mdns_repeater_interfaces="net0 net1"