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45 lines
1.5 KiB
ReStructuredText
45 lines
1.5 KiB
ReStructuredText
mDNS Repeater
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-------------
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Starting with VyOS 1.2 a :abbr:`mDNS (Multicast DNS)` repeater functionality is
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provided. Additional information can be obtained from
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https://en.wikipedia.org/wiki/Multicast_DNS.
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Multicast DNS uses the 224.0.0.251 address, which is "administratively scoped"
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and does not leave the subnet. It retransmits mDNS packets from one interface
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to other interfaces. This enables support for e.g. Apple Airplay devices across
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multiple VLANs.
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Since the mDNS protocol sends the AA records in the packet itself, the repeater
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does not need to forge the source address. Instead, the source address is of
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the interface that repeats the packet.
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Configuration
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=============
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.. cfgcmd:: set service mdns repeater interface <interface>
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To enable mDNS repeater you need to configure at least two interfaces. To
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re-broadcast all incoming mDNS packets from any interface configured here to
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any other interface configured under this section.
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.. cfgcmd:: set service mdns repeater disable
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mDNS repeater can be temporarily disabled without deleting the service using
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.. note:: You can not run this in a VRRP setup, if multiple mDNS repeaters
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are launched in a subnet you will experience the mDNS packet storm death!
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Example
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=======
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To listen on both `eth0` and `eth1` mDNS packets and also repeat packets
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received on `eth0` to `eth1` (and vice-versa) use the following commands:
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.. code-block:: none
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set service mdns repeater interface 'eth0'
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set service mdns repeater interface 'eth1'
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.. _`Multicast DNS`: https://en.wikipedia.org/wiki/Multicast_DNS
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