Sending AT commands to 5G modem.

[Doner005]

Hey Everyone,

I’m pretty new to customizing Asuswrt-Merlin so bear with me. My main goal is to be able to send AT commands to my 5G modem remotely that is connected to my router WAN port. So far I have DDNS setup so I can log into the web ui remotely but I have yet to figure 2 things I need to do to accomplish my goal.

First I need to be able access the modem via udp from the CLI. As of now I do this while on my home network either from MAC terminal or iOS/ipad app called ish using the Linux command “nc -u 192.168.100.1 5555”. I’ve tried to use this same command through ssh but I’m not sure if that’s the correct way or if I need to do something else first?

Second I need access to the CLI from the Web UI. Is this possible to add via addons? Thanks for any help you can provide.

 

[ColinTaylor]

Enabling remote web access to the router's GUI is strongly discouraged for security reasons. For the same reason router CLI access via the GUI is not allowed. The preferred method of remote access is via the router's VPN server.

I don't see why your nc command wouldn't work via SSH. Do you get an error message?

 

[Doner005]

Enabling remote web access to the router's GUI is strongly discouraged for security reasons. For the same reason router CLI access via the GUI is not allowed. The preferred method of remote access is via the router's VPN server.

I don't see why your nc command wouldn't work via SSH. Do you get an error

Enabling remote web access to the router's GUI is strongly discouraged for security reasons. For the same reason router CLI access via the GUI is not allowed. The preferred method of remote access is via the router's VPN server.

I don't see why your nc command wouldn't work via SSH. Do you get an error message?

I get the error invalid option — ‘u’

I had to enable remote access for the asus app to work. I’m assuming that their app is safe to use correct? Is there a way to use that but turn off access to the web gui remotely?

I believe non of this is actually going to work remotely for my because of T-Mobile CGNAT. Do you have any ideas on how I can get that access remotely with CGNAT?

 

[L&LD]

No app is safe to use.

Let alone an app that needs WAN access to your network.

 

[ColinTaylor]

I get the error invalid option — ‘u’

Ah, I see. Yes the router's nc doesn't support the UDP option. So you'd have to use nc on your client device, like you do now on the mac/ipad.

I had to enable remote access for the asus app to work. I’m assuming that their app is safe to use correct? Is there a way to use that but turn off access to the web gui remotely?

My understanding is that you don't need to leave remote access enabled to use the app locally or over a VPN connection.

I believe non of this is actually going to work remotely for my because of T-Mobile CGNAT. Do you have any ideas on how I can get that access remotely with CGNAT?

If you have CG-NAT then direct remote access isn't possible making the whole question moot.

 

[Tech9]

Do you have any ideas on how I can get that access remotely with CGNAT?

IPv6 VPN Server with IPv6 DDNS service, eventually.

 

[Tech Junky]

goal is to be able to send AT commands to my 5G modem remotely that is connected to my router WAN port.

From you / other users the modem is hitting a load balancer that shares the IP on the public side.

Internally though TMO uses IPv6 though which presents some other issues in getting back inside from the outside.

The only way I see this working is some sort of reverse tunneling most likely in this case though creating a VPN tunnel out to an external endpoint and then jumping to your internal network through the tunnel. Once you have a path established it should work. The only issue then is if you issue an AT to reset the modem and the VPN doesn't establish again to the endpoint.

If you go to speedtest.net it will show you the external IP 172.x.x.x

It can be done but not for free or DDNS. Minimal costs though to rent a server and connect the router to the server instance to make it happen are an option though. The other option would be to convert the account over to a business account and get a static IP from TMO that allows access directly.