I have a GL inet Spitz X3000 whose only Wan port is connected to a Melon 658 router with which an ALFA AWUS036NH USB dongle is connected that receives a wifi network shared with a wifi router of a relative on the ground floor. As a second network I have a 5G sim card activated inside the GL inet Spitz X3000. Everything is configured in failover, so if the connection of the first network drops, the sim card connection intervenes.
Inside my house I would like to create a wifi network without using the wifi of the Gl inet X3000. (I want to keep it off so as not to overload it and overheat it). I have a TPlink MR3020 router which from stock has the ability to set a selector on 3G / 4G with an external sim card modem, on WDS and on AP (access point) and therefore with this last option connect with a wired wan and distribute the connection via wifi. on this Tplink MR 3020 I installed the open wrt firmware. I want to specify that all the internal devices of the house are connected with a switch (because the GLinet has only one LAN port). So I would like to connect the TPlink MR 3020 to the internal network of the house to a free port of the switch and know how to set it so that it takes the connection from its only Ethernet port and distributes via wifi in AP mode. At the moment in the submenu interfaces of open wrt it has WAN with no settings and LAN with the static IP 192.168.1.1 set (which it inherited from the stock firmware during the change with the open wrt firmware). I had changed the IP of the TP link MR3020 from static to dynamic by connecting directly to the Ethernet card of the PC and a big problem happened because I could no longer enter the LUCI web page because I could not find which IP it had. I thought I had bricked it but then I connected it to the switch instead, I opened the client tab of the GLinet Spitz x 30000 and I found it listed with a dynamic IP given in DHCP by the Gl inet X3000. So I did the recovery from the backup I had made of the TPlink MR 3020 immediately after switching to openwrt and it returned to its static IP 192.168.1.1. I would like to know how to set it up so that the TPlink connects with its only ETHERNET port to the switch and then makes a wifi network available inside the house. With the original TPlink firmware I know how to do it, but with openwrt unfortunately not, and I don't want to do any damage. I would also like to know if the physical selector of the TP link MR3020 with the openwrt firmware is active) Moving it, I noticed that the LEDs light up based on where it is selected. However I think I understood that if you set it to dynamic IP and put the selector on AP it is no longer reachable via its LUCI web-page from the PC's network card, because it would be seen as a gateway; instead connected to a gateway router it is displayed with its assigned DHCP dynamic IP, and through this identified IP you can enter its web-page.