Hi, wonder if anyone can give me any pointers what I might be missing.
I have Quectel EC25 on top of RPi OS (Bookworm, RPi4). I followed the instructions on these pages and modem is registered to the network, has IP address and route is set. Ip_raw is Y and so forth.
Still I cannot get any ping to go trough (well actually, if I check tcpdump, ping seems to be leaving but I do not get anything back).
ip route show
default via 100.103.226.156 dev wwan0 proto static metric 50
default via 192.168.1.1 dev wlan0 proto dhcp src 192.168.1.174 metric 600
100.103.226.152/29 dev wwan0 proto kernel scope link src 100.103.226.155 metric 50
192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.174 metric 600
but when trying to make a ping → “ping -I wwan0 8.8.8.8”, I do not get a response.
Any ideas what could be the problem are appreciated
It looks like your modem is successfully registering to the network and receiving an IP address but the ping issue might be due to routing conflicts or misconfigured settings. Here are a few things you can check and adjust:
USB Mode (usbnet setting)
Ensure the USB mode is configured correctly. Run:
AT+QCFG="usbnet"
It should return 0. If it doesn’t, you can change it by running:
AT+QCFG="usbnet",0
AT+CFUN=1,1
After applying this, reboot the module after about 10 seconds.
Verify Raw IP Configuration
Check that the raw_ip is set to ‘Y’ before bringing up the interface:
sudo ip link set wwan0 down
echo 'Y' | sudo tee /sys/class/net/wwan0/qmi/raw_ip
sudo ip link set wwan0 up
Routing Conflicts
It seems there might be a conflict with the default routes. You have two default routes:
default via 100.103.226.156 dev wwan0 metric 50
default via 192.168.1.1 dev wlan0 metric 600
To test, try disabling your Wi-Fi interface temporarily to ensure that wwan0 is the default:
sudo ip link set wlan0 down
Then, try pinging again using ping -I wwan0 8.8.8.8.
Check DNS Settings
If you’re still having trouble with DNS resolution, make sure /etc/resolv.conf is correctly configured to use the DNS servers provided:
124.6.181.26
124.6.181.25
MTU Settings
Some networks require a specific MTU size to function correctly. Try adjusting the MTU size on wwan0:
sudo ip link set wwan0 mtu 1428
Reinitialize Connection with qmicli
If the above doesn’t resolve the issue, you can reinitialize the connection using qmicli:
I do not know what is going on but today the modem is not recognised by Linux. Cannot see it with lsusb and there is no traces in the logs.
So need to troubleshoot a bit what is going on before I can reply to you. I did try all of those of course except did not put wlan0 link down, I just removed it from the route. Result was the same.
About the modem not found at the moment, in a worst case perhaps there was something wrong with the unit already and that was causing this issue.
Or I also have another theory. My device is actually EC25EU, as I need it in Europe but currently I am in another country where there is both FDD and TDD LTE. When modem was still working I checked, it is camped to TDD site and also TDD is not allowed, at least this is how I read following: +QCFG: “band”,0x93,0x1a0080800c5,0x0
I do not know if there is FDD coverage in the same area where I am but doubt operator would build mixed coverage with FDD and TDD, well who knows. But this would sound logical to me.
Anyway need to come back on this if I get it back in working order.
