MT3000 does not support ranges for port-forwarding

As the title says, GliNet GL-MT3000 does not support ranges for port-forwarding, even though the underlying OpenWRT supports them just fine. Ranges are useful for things like passive FTP.

Yes, actuall we have planned it in the next firmware v4.6.0 which shall be released soon.
Now you can login the Luci interface to setup the ranges for port forwarding.