No IP address for a successful connection on LTE modem

Garfield Watkins garfield.watkins at
Wed Feb 14 10:20:56 UTC 2024

I think what confused me is that without the ModemManager i.e. using 
just cgact=1,1 to manually connect, i suddenly got an ip address 
assigned to the network interface provided by the modem. I thought it 
was NetworkManager running its dhcp client on that interface after 
getting a dhcp discover ? from the modem ? (i'm not too sure about how 
dhcp goes about its business)

Anyway i have now tried to use Network Manager to setup and connect but 
now am getting the following message:

modem-broadband[ttyUSB0]: failed to connect 'meig': Connection requested 
both IPv4 and IPv6 but dual-stack addressing is unsupported by the modem.

and disabling ipv6 I get:

  failed to connect 'meig': Connection requested IPv4 but IPv4 is 
unsupported by the modem.

Any idea where to start debugging that ?

On 2/14/24 11:24, Aleksander Morgado wrote:
> Hey!
> On Tue, Feb 13, 2024 at 1:49 PM Garfield Watkins
> <garfield.watkins at>  wrote:
>> Did you connect the modem using NetworkManager (e.g. using nmcli) or
>> did you connect the modem using mmcli?
>> I see where you are going with this. It seems I expected more of the interaction between the ModemManager and Network Manager . To answer your question, no I have only used mmcli. Let me try the process with nmcli.
> :) NM only processes the connections that have been started via NM.
> There's a fundamental reason for that, which is that all the
> network-specific routing is done at NM level, MM knows nothing about
> it. In order for NM to know how to route traffic to through the LTE
> connection, it needs to use its own connection settings.
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