Background: I bought a TP-Link Archer MR200 4G router and hooked it up with an EE SIM. Although the EE signal was poor (even with an external antenna), I could access the Internet from my LAN, and vice-versa - specifically, I could hit the router WAN address with an HTTP connection.
After hearing that the O2 signal was much better in this location, I bought a regular O2 PAYG SIM and tried that; after replacing the default config with the PAYG hostname & credentials, it fired up with 3 bars of signal and - whoopie, I had 30-40 Gbit/s downlink, 20 uplink! However, I couldn't get to the WAN address from outside, no matter what I tried. After setting up No-IP Dynamic DNS, it detected my IP address as something completely different.
After several unsuccessful attempts to engage O2 for help, I managed to speak to someone who understood what I was talking about and she revealed that there is a 'Data Only' SIM, which is designed for dongle, tablet etc use; the trouble is that it's twice the cost for much less data! Also, she didn't know whether I'd be able to connect to it remotely. Subsequent attempts to find such information from CS have resulted in silence, confusion or - in one case - an assertion that what I was doing was 'impossible', despite my talking to him via EE's 'WiFi calling' through the very link he said couldn't exist.
Can anyone help? Is there an O2 SIM whose LTE WAN address is visible from the Internet and if not, how might I set up a VPN tunnel instigated from say an internal Linux server which I can then connect to remotely from a laptop or another Linux server? I plan to run a backup RAID, perhaps a security camera or two on the LAN, so they need to be accessible via Port Forwarding.
Any help gratefully received and I may be able to barter something, especially if you're anywhere near Somerset.
TIA, David.
