No Subnet other than /8 /16 /24


I tried to expand my network a little bit and so i tried to set up subnet mask but the input field will not accept this. It ‘corrects’ all the time to or

Any suggestions?

Thank you!


Device: RUT240 FW RUT2_R_00.07.04.5


In order to set a mask that is not one of the mentioned above, you’ll need to enter it into the -- Custom -- field:

Once you’ve filled out the field, press enter. Save and Apply the configuration, and the LAN mask will be changed:

Hope this helps!

Best regards,

Hey Daumantas,

Thank you. That’s not very intuitive. May it could be added to the Wiki?

It Worked for me. Thank you again!


You need to change this. The only reason I finally managed to set a custom subnet was because of this post.

The intuitive would be to select custom, and then write in the subnet-mask textbox, not in the pulldown menu itself!

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