SixXS::Sunset 2017-06-06

SixXS Heartbeat Information

For maintaining a proper and stable IPv6 Tunnel Brokering system we have created a heartbeat mechanism which sends a packet to the PoP, which then enables the tunnel on the PoP side.

When there is no heartbeat for 300 seconds the PoP automatically disables the tunnel. If the IPv4 address changes, the tunnel is again automatically reconfigured to the new address. If the tunnel was down it is configured to be up on the heartbeat.

All of this makes sure that traffic won't be transmitted to unsuspecting endpoints in case an endpoint is on a dialup connection or other fast-changing endpoint.

Warning Keep your machine NTP synced, if the timestamp difference is bigger than 120 seconds the heartbeat will be silently dropped. Note also that you need to select the correct time zone.

Comments and questions should be directed to or the SixXS Forums for discussions.

The SixXS Heartbeat Protocol as described in the draft uses the IANA assigned port 3740 for communication to notify a PoP of IPv4 endpoint changes and the reachability of the client.

The former 'heartbeat' clients are no longer available, please download the AICCU client which can do more and in a better way.

Heartbeat Protocol implementations

The following tools have implemented the heartbeat protocol:

Static Sunset Edition of SixXS
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