mirror of
https://github.com/vyos/vyos-documentation.git
synced 2025-10-26 08:41:46 +01:00
b6759431b0
The address 224.0.0.51 is a Zeroconf address, and not the address associated with mDNS (224.0.0.251) The Multicast address registry from IANA can be found here: https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml under `Local Network Control Block`
45 lines
1.5 KiB
ReStructuredText
45 lines
1.5 KiB
ReStructuredText
mDNS Repeater
|
|
-------------
|
|
|
|
Starting with VyOS 1.2 a :abbr:`mDNS (Multicast DNS)` repeater functionality is
|
|
provided. Additional information can be obtained from
|
|
https://en.wikipedia.org/wiki/Multicast_DNS.
|
|
|
|
Multicast DNS uses the 224.0.0.251 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
|
|
=============
|
|
|
|
.. cfgcmd:: 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.
|
|
|
|
.. cfgcmd:: 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:
|
|
|
|
.. code-block:: none
|
|
|
|
set service mdns repeater interface 'eth0'
|
|
set service mdns repeater interface 'eth1'
|
|
|
|
.. _`Multicast DNS`: https://en.wikipedia.org/wiki/Multicast_DNS
|