Hi @SmartZone 

Thanks for posting in our business forum.

1. You can still enable DHCP snooping by CLI if the feature is not available on the Omada controller. Requiring you to access the switch by console.

2. About the Legal DHCP not working, how do you draw this conclusion? Have you used Wireshark to analyze and conclude that? Have you done a test to verify that?

If you'd like to do a test, try this to reproduce the issue you report:

One computer, one router, and one of the TL-SG switch you have.

Set a VLAN interface on the Omada router and set it to the port with Legal DHCP server configured. Lease time is 1 minute.

Connect a router(simulate the illegal DHCP server. With a different subnet.) and a PC to the same VLAN you just created. You can Wireshark on this PC and monitor its DHCP interaction.