In most cases this is the way ...
- connect smartphone to OPAL wifi
- in the GL.inet GUI, set the Network mode to "router" , not to "extender"
- In the GL.inet GUI start the repeater , and scan for the MSC wifi
- Set the "Auto-Enable Login Mode for Public Hotspots" option on (it will disable VPN and DNS setting, until portal login is done)
- select and connect to the MSC wifi with the OPAL
- You will not have internet access because the MSC portal Login is not done yet
- You may have to reconnect to the OPAL now with the smartphone if the same band is used for the smartphone as for the MSC wifi (OPAL will change channel to the MSC wifi channel)
- ON the smartphone surf to some HTTP based website (not HTTPS) while connected to the OPAL with the smartphone
- This will trigger the MSC login page. MSC sees only the OPAL, independent of whatever device is used through the OPAL. The login will be registered for the OPAL.
- Any device connecting through the OPAL will be seen by MSC as coming from the OPAL
Maybe they don't like this, and will try to discover the fact that it is not the OPAL itself. They will check the TTL of packets and other things, maybe even the MAC address used and compare it to the VENDOR list of the hardware MAC address, in an attempt to detect a travel router. TTL if not mitigated changes when "extender" or with Network mode "router".
The host network (MSC wifi) only sees the OPAL when in Network Mode "router", and everything comes and goes to the OPAL So MAC vendor list and TTL check is the only thing that will reveal the OPAL. You can use the connect option "Enable Camouflage" to hide the OPAL MAC address and use the smartphone MAC address instead. There is also an option to set a fixed TTL.
Oh well, the DHCP client name says GL-SFT1200 by default, so change that as well, just in case they would check that. I doubt if they do that, but I do this.
(You can only change DHCP hostname in Luci AFAIK)
System-> Advanced -> Luci -> Interfaces -> WWAN -> General setup -> "Hostname to send when requesting DHCP "
There are exemples in this forum how to fix TTL via SSH, Change TTL in the case they check it. Change outgoing TTL