Systemd networkd TunnelBroker Hurricane Electric 6in4

eth1.network

# This can be any public reachable interface
# basically the one connected to the internet (native or bridged)
[Match]
Name=eth1

[Network]
# your normal interface address example: 10.1.1.2/24
Address=<LOCAL_IPV4>/<NETMASK> 
Gateway=<LOCAL_IPV4_GW> # local ip gw e.g 10.1.1.1

# below is tunnel specific
Tunnel=he6
# One of the tunnel routed ipv6 address (e.g. 2001:470:xxx::1/64 or /48)
Address=<ROUTED_IPV6_ADDRESS> 

he.netdev

# Define and create tunnel interface
[Match]

[NetDev]
Name=he6
Kind=sit
MTUBytes=1480

[Tunnel]
Remote=<SERVER_IPV4_ADDRESS>
Local=<LOCAL_IPV4>
TTL=255

he.network

# This is your tunnel network configuration
[Match]
Name=he6

[Network]
Address=<CLIENT_IPV6_ADDRESS>
Gateway=<SERVER_IPV6_ADDRESS>

# optional ip forward
IPForward=yes 

# Policy based routes below are only required if you have existing ipv6 setup 
# and want to ensure incoming routing works properly

[Route]
Gateway=<SERVER_IPV6_ADDRESS>
Destination=::/0
Table=200
Metric=20

[RoutingPolicyRule]
Table=200
Family=ipv6
From=<CLIENT_IPV6_ADDRESS>

[RoutingPolicyRule]
Table=200
Family=ipv6
From=<ROUTED_IPV6_PREFIX>