Dynamic DNS (DDNS) on the Ubiquiti UDM-SE

Dynamic DNS (DDNS) functionality on the UDM-SE is provided by Inadyn running as apart of a systemd service (udapi-server.service – Ubiquiti udapi server).

1. Inadyn Triggered (via UDM restart, WAN IP Changed)
2. Inadyn checks local cache for previous WAN IP value
3. if WAN IP == cached IP, do nothing
   >> Sample output
4. If WAN_IP != cached WAN_IP, update cached WAN_IP and initiate DDNS update with your host**
   >> Sample output

** This means Inadyn never checks the IP provided by your DNS Host if your WAN IP hasn’t changed – making it impossible to test without reassigning the WAN IP

When setup via the Unifi Network Application for the WAN1 port (port #9), the target configuration filename will look like this
NOTE: The target configuration filename changes based on the switch port your WAN IP is coming from.

```
# systemctl status -l udapi-server.service
/usr/sbin/inadyn -n -s -C -f /run/ddns-eth8-inadyn.conf
```