[OPNsense] one of the trampling records: interface, DHCP Service, DHCP RELAY

During the DHCP relay test for OPNsense, it was found that the DHCP relay could not be started, indicating that the DHCP service was running. As shown below:

1. Troubleshoot Interfaces:

It is found that there is an interface in the down state in Interfaces. After enabling it, check the DHCP service under Services and find that the DHCP service for this interface is enabled. After shutting down, the DHCP RELAY function will be available immediately. At the same time, go to Firewall to check the previous configuration and find that the configured rules are still there.

2. Additional testing:

First turn off DHCP RELAY, and then turn on the DHCP service for this interface so that DHCP RELAY cannot be enabled. Then enter Interfaces, deactivate the interface and enter assignments to remove the interface directly. Finally, go directly to DHCP RELAY, no longer prompt that the DHCP service is running, and you can enable DHCP RELAY.

From this, we can see that there is a difference between the deactivation and removal of OPNsense's interfaces:

1. Deactivation will hide the relevant configuration of the interface on the GUI, but retain all the configurations of the interface.

2. Removing will delete all configurations of this interface.

Digression: when I asked this question, the official administrator said that he was not clear about the situation.