Can't place RM520 in IP Passthrough (IPPT) mode

The solution is to use the following command:

at+qmap=“mpdn_rule”,0,1,0,1,1,“FF:FF:FF:FF:FF:FF”

If “FF:FF:FF:FF:FF:FF” is used, then the first connected host’s Ethernet interface MAC address will be used to bridge the WWAN interface to, so only the first connected host’s Ethernet interface will be able to get the IP addressed leased to the 5G modem by the cellular carrier. No other network interfaces can receive the DHCP lease bridged from the WWAN interface to the Ethernet interface by the 5G modem until the modem is restarted.

or

at+qmap=“mpdn_rule”,0,1,0,1,1,“A1:B2:C3:D4:E5:F6”

where A1:B2:C3:D4:E5:F6 is the MAC address of the connected Ethernet interface. In this case, only the host with the specified Ethernet interface MAC address will be able to get the IP addressed leased to the 5G modem by the cellular carrier. This setting survives the 5G modem restart, so only the host with the specified MAC address can get a DHCP lease from the 5G modem with the IP information that the 5G modem gets from the carrier.