One-way traffic on with the EM7411

[Dan Williams]

On Fri, 2021-09-03 at 21:12 +0000, Liam wrote:
> Hi,
>  
> libqmi has performed fantastically with the EM7455. Using the typical
> ‘qmi-network start’ and then a dhcp client to get an address works
> pretty seamlessly.
>  
> My problem is that I have been asked to eval the EM7411 and I cannot
> get DHCP to resolve and traffic is only coming from the interface,
> not to it. This is the general steps:
> 

Is there any particular reason you're using DHCP, rather than pulling
the IP info from the modem via libqmi?

Also, what DHCP client are you using?

Lastly, what mode are you running the WWAN interface in, raw-ip or
802.3?

Dan

>  
>    1. Start qmi-network successfully and confirm the network IP
> address with --wds-get-current-settings
>    2. Perform DHCP on the ‘wwan0’ interface and fail
>    3. Manually set the wwan0 interface IP to that returned by wds-
> get-current-settings
>    4. Can see pings comes through the interface, but do not see them
> or any other traffic coming from it
>  
> ON THE EM7411 DEVICE
> tcpdump: verbose output suppressed, use -v or -vv for full protocol
> decode
> listening on wwan0, link-type RAW (Raw IP), capture size 262144 bytes
> 09:23:18.783894 IP 10.222.3.169 > 10.222.9.147: ICMP echo request, id
> 27414, seq 36, length 64
> 09:23:18.784106 IP 10.222.9.147 > 10.222.3.169: ICMP echo reply, id
> 27414, seq 36, length 64
> 09:23:19.742704 IP 10.222.3.169 > 10.222.9.147: ICMP echo request, id
> 27414, seq 37, length 64
> 09:23:19.742915 IP 10.222.9.147 > 10.222.3.169: ICMP echo reply, id
> 27414, seq 37, length 64
>  
> TO THE EM7511 DEVICE
> listening on wwan0, link-type RAW (Raw IP), capture size 262144 bytes
> 21:09:33.866587 IP 10.222.3.169 > 10.222.9.147: ICMP echo request, id
> 27414, seq 333, length 64
> 21:09:34.870089 IP 10.222.3.169 > 10.222.9.147: ICMP echo request, id
> 27414, seq 334, length 64
>  
> Anyone have a clue what could be causing this issue? 
>  
> -Liam 
>  
>