Huawei B315s 4G Router

[ITGURU]

I have a B315s 4g router i want to add as a backup connect to the network remotely for management in case of lease line failure using SSL vpn port 443

I can connect from inside to out connected to the 4g router however an issue with the external to internal access.

DYNDNS is setup, connected and updating the dns domain name with the correct WAN IP.

Within the router settings I have unticked 'disable wan port ping' however i cannot ping the external IP from another device on 4g to check the connection.

The routers default IP is 192.168.8.x and lan for example is 192.168.0.x so if i need to do a firewall rule from external to internal on i presume I need to change the IP to the 192.168.0.x range and which port on the 4g router should the cable be connected from the LAN to it?

Thanks.

[computer_expert]

Do you know if your 4G provider uses CGNAT? If they do, you may well be out of luck with port forwarding. I think most mobile networks in the UK do use CGNAT sadly.

 

Is the 4G router WAN IP the same as your 4G public/external IP? This isn't quite clear in your original post but will be a good indication if you are behind an extra layer of NAT further upstream.

[ITGURU]

Do you know if your 4G provider uses CGNAT? If they do, you may well be out of luck with port forwarding. I think most mobile networks in the UK do use CGNAT sadly.

 

Is the 4G router WAN IP the same as your 4G public/external IP? This isn't quite clear in your original post but will be a good indication if you are behind an extra layer of NAT further upstream.

I'm guessing this is the case with all standard uk SIM cards? will incoming rules only work if I get a proper contract M2M SIM card?

[MatthewL]

You will need a static IP on the SIM card, some but not all providers can do this.

[ITGURU]

I didnt think that a static ip would be required as it has DDNS - assume it just needs to be a SIM which allows incoming connections?

[Norphy]

It doesn’t need a static ip (although it would help!) but the carrier can’t use carrier grade NAT.

 

It’s not a question of allowing incoming connections, the 4G router needs a direct connection to the internet, not sit behind NAT.

 

An easy way to check is to do a trace route. If one of the hops is a private IP address range outside of your network, you know you’ve got carrier grade NAT.

[MatthewL]

You fill find most SIM's use carrier grade NAT, even if you didn't and got a public IP it's assigned to a pool of devices so you would need a static for it to work.