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ALFRED(8) Almighty Lightweight Fact Remote Exchange Daemon ALFRED(8)


alfred - Almighty Lightweight Fact Remote Exchange Daemon


alfred [options]


alfred is a user space daemon for distributing arbitrary local information over the mesh/network in a decentralized fashion. This data can be anything which appears to be useful - originally designed to replace the batman-adv visualization (vis), you may distribute hostnames, phone books, administration information, DNS information, the local weather forecast ...

alfred runs as daemon in the background of the system. A user may insert information by using the alfred binary on the command line, or use special programs to communicate with alfred (done via unix sockets). alfred then takes care of distributing the local information to other alfred servers on other nodes. This is done via IPv6 link-local multicast, and does not require any configuration. A user can request data from alfred, and will receive the information available from all alfred servers in the network.


-v, --version
Print the version
-h, --help
Display a brief help message.
-u, --unix-path path
path to unix socket used for client-server communication.


-s, --set-data data-type
Sets new data to distribute from stdin for the supplied data type (0-255).

Note that 0 - 63 are reserved (please send an e-mail to the authors if you want to register a datatype), and can not be used on the commandline. Information must be periodically written again to alfred, otherwise it will timeout and alfred will forget about it (after 10 minutes).

-r, --request data-type
Collect data from the network and prints it on the network
-d, --verbose
Show extra information in the data output
-V, --req-version version
Specify the data version set for -s

Skipping the parameter entirely has the same effect as setting the parameter to 0 ('-V 0').

-M, --modeswitch mode
    Switch daemon to mode primary
    Switch daemon to mode secondary
-I, --change-interface interface
Change the alfred server to use the new interface(s)


-i, --interface face
Specify the interface (or comma separated list of interfaces) to listen on
-b batmanif
Specify the batman-adv interface configured on the system (default: bat0). Use 'none' to disable the batman-adv based best server selection.

The -b option is optional, and only needed if you run alfred on a batman-adv interface not called bat0, or if you don't use batman-adv at all (use '-b none'). In this case, alfred will still work but will not be able to find the best next primary server based on metrics.

-m, --primary
Start up the daemon in primary mode, which accepts data from secondaries and syncs it with other primaries.

alfred servers may either run as primary or secondary in the network. Primaries will announce their status via broadcast, so that secondaries can find them. Secondaries will then send their data to their nearest primary (based on TQ). Primaries will exchange their data (which they have received from secondaries or got on their own) with other primaries. By using primaries and secondaries, overhead can be reduced while still keeping redundancy (by having multiple primaries). Obviously, at least one primary must be present in the network to let any data exchange happen. Also having all nodes in primary mode is possible (for maximum decentrality and overhead).

-c, --update-command command
Specify command to execute on data change. It will be called with data-type list as arguments.
-p, --sync-period period
Specify alfred synchronization period, in seconds. If not specified, the default ALFRED_INTERVAL setting of 10 seconds will be used. Fractional seconds are supported.
-4 group-address
Specify the IPv4 multicast group address and enable IPv4 data-sharing (disabling IPv6 communication). This option is required on systems that do not support IPv6 addressing.


Start an alfred server listening on bridge br0 (assuming that this bridge includes the batman interface bat0):
alfred -i br0 -m

Send data to the alfred server and store it under id 65:
cat /etc/hostname | alfred -s 65

Retrieve all data stored as id 65 from all connected alfred servers:
alfred -r 65

     { "fe:f1:00:00:01:01", "OpenWRT-node-1\x0a" },
     { "fe:f1:00:00:02:01", "OpenWRT-node-2\x0a" },
     { "fe:f1:00:00:03:01", "OpenWRT-node-3\x0a" },


batadv-vis(8), batctl(8)


alfred was written by Simon Wunderlich <> and Sven Eckelmann <>.

This manual page was written by Simon Wunderlich <> and Sven Eckelmann <>.

September 21, 2013 Linux