Subject: Issue with Ping Failures on Quectel Module (Unable to Ping from Evaluation Board to Host PC and vice-versa)
Problem Statement: We are encountering a persistent issue with our cellular module setup where the module is unable to ping its own IP address or the connected host PC’s IP over a USB ECM (usbnet=0) interface. Despite successful IP assignment and verified network registration, AT+QPING consistently fails with response code 569.
This issue is blocking two-way communication testing between the evaluation board and the host system, and may indicate an internal routing or ICMP handling issue in the firmware.
Environment and Setup
Parameter Value/Notes
Module Manufacturer Quectel EC25
Firmware Version EC25EFAR06A06M4G
Interface Mode USB ECM (AT+QCFG=“usbnet”,0)
OS Windows 11
Cellular Network Vodafone IN (LTE)
SIM Status Active + Internet Plan Enabled
Evaluation Platform QNavigator_V1.6.8
Steps Already Performed
- Verified Windows recognizes the ECM interface and assigns IP (10.161.170.51).
- Host PC can successfully ping module:
ping 10.161.170.51 → Successful - Module fails to ping PC or its own IP:
AT+QPING=1,“10.161.170.51” → +QPING: 569 - Attempted AT+QIACT=1 → returns ERROR
- Verified AT+QCFG=“usbnet” is set to 0 (ECM mode)
- Checked signal strength, registration, and attachment:
AT+CSQ, AT+CREG?, AT+CGATT? → all OK - Tried AT+QNETDEV? → returns ERROR
- Windows Firewall was fully disabled to rule out any interference with ICMP requests or adapter detection — but the issue persists.
Current Issues
- AT+QPING from the module always fails with code 569 (no route or ICMP timeout).
- Even pinging its own IP (loopback) fails.
- The module appears reachable from host, but cannot initiate outbound pings, even with a correct PDP context.
- Attempted with all available USB network modes using AT+QCFG=“usbnet”, (i.e., modes 1, 2, and 3), but:
• In all other modes (besides 0), the network adapter on the host becomes unstable — it appears briefly for 5 seconds, then disappears for 2–3 seconds, and keeps cycling this way.
• In these unstable modes, no reliable ping or connectivity is possible from either side. - The module’s network adapter on Windows stays in the “Identifying…” state and does not transition to a “Private” network profile, which may be preventing full IP stack initialization or ICMP/routing functionality on the host side.
Questions for Qualcomm Support
- Is AT+QPING expected to work in ECM mode to the module’s own IP?
- Could firmware or hardware routing/filtering cause the 569 result?
- Does ECM mode require additional setup to support ICMP from module?
- Is there a known limitation or patch for this behaviour?
- Should AT+QNETDEV? work in ECM mode?
- What does QPING: 569 exactly indicate internally?
- How can we enable successful ICMP communication from the host PC to the IP address assigned to the module (evaluation board)?