mDNS Repeater

Starting with VyOS 1.2 a mDNS repeater functionality is provided. Additional information can be obtained from https://en.wikipedia.org/wiki/Multicast_DNS.

Multicast DNS uses the 224.0.0.51 address, which is “administratively scoped” and does not leave the subnet. It retransmits mDNS packets from one interface to other interfaces. This enables support for e.g. Apple Airplay devices across multiple VLANs.

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.

Configuration

set service mdns repeater interface <interface>
To enable mDNS repeater you need to configure at least two interfaces. To re-broadcast all incoming mDNS packets from any interface configured here to any other interface configured under this section.
set service mdns repeater disable
mDNS repeater can be temporarily disabled without deleting the service using

Note

You can not run this in a VRRP setup, if multiple mDNS repeaters are launched in a subnet you will experience the mDNS packet storm death!

Example

To listen on both eth0 and eth1 mDNS packets and also repeat packets received on eth0 to eth1 (and vice-versa) use the following commands:

set service mdns repeater interface 'eth0'
set service mdns repeater interface 'eth1'