Configure static ipv6 ULA address

01-systemd-unit.sh

# Create systemd unit
cat << EOF > /etc/systemd/system/theg2-ipv6-ula.service 
[Unit]
Description=Add ipv6 static ULA
After=network-online.target
Requires=network-online.target

[Service]
Type=oneshot
ExecStart=/sbin/ip address add fd0b:dead:b0b1::123 dev wlan0
RemainAfterExit=true

[Install]
WantedBy=multi-user.target
EOF

# Enable service
systemctl daemon-reload
systemctl start theg2-ipv6-ula
systemctl start theg2-ipv6-ula

02-systemd-networkd.sh

# Create systemd-networkd unit
cat << EOF > /etc/systemd/network/10-static-wlan0.network
[Match]
Name=wlan0

[Network]
Address=fd0b:dead:b0b1::123/64
EOF

# TODO: enable/test
systemctl daemon-reload
systemctl start theg2-ipv6-ula
systemctl start theg2-ipv6-ula

03-if-up.d.sh

cat << EOF > /etc/network/if-up.d/theg2-ipv6-ula
#!/bin/sh

# Only configure IPv6 for the desired interface
if [ "$IFACE" != "eth0" ]; then  # wlan0 or eth0 or enp1s0
    exit 0
fi

ip -6 addr add fd0b:dead:b0b1::123 dev $IFACE
EOF

chmod +x /etc/network/if-up.d/theg2-ipv6-ula

# Test using:
IFACE=wlan0 /etc/network/if-up.d/theg2-ipv6-ula

Also need to configure static route on UnifiOS:

After adding to unifios network settings as manual ipv4 and ipv6 dns servers should show up in resolvectl or on older systems: