Modifying subnet mask on Opal (GL-SFT1200)

I see where I can modify the LAN IP of the Opal (GL-SFT1200) router but I’ve tried changing the subnet mask by entering “” to enter a mask of and the “/16” isn’t accepted. I don’t see a “subnet” or “subnet mask” box in the web interface as shown here:

The above picture came from:

Does anyone know where I can find the options for modifying the subnet mask? Thanks,


Because contains, there is a conflict with the guest subnet. You need to set the guest and then the lan.

I appreciate the quick reply but where you have a “netmask” field below the default gateway textbox, I don’t have a field to enter or /16. The gateway is at a customer site at the moment but I should be able to swing by tomorrow to take a screenshot.

I’m pretty sure when I clicked on “Guest Network” there was a radio button and “Enable” was set to “off” so I just left it disabled (it’s not needed).

I have SSH access to everything on the network, including the Opal, but I don’t have a way to look at the web GUI remotely.

Here’s what’s shown when I ssh into the Opal for the “guest” network:

root@GL-SFT1200:~# ubus list network.interface.*
root@GL-SFT1200:~# ifstatus guest
“up”: false,
“pending”: false,
“available”: false,
“autostart”: true,
“dynamic”: false,
“proto”: “static”,
“device”: “br-guest”,
“data”: {

    "errors": [
                    "subsystem": "interface",
                    "code": "NO_DEVICE"