Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Achim Kraus — Wed, 04 Jun 2025 08:06:15 GMT

[quote userid="132958" url="~/f/nordic-q-a/121809/help-with-coap-client-sample-on-nrf9160-dk-using-jio-nb-iot-sim/537974"]That’s why I suspect the issue may be that Jio’s NB-IoT network allows DNS (UDP port 53), but blocks CoAP (UDP port 5683) or general UDP traffic to public servers.[/quote]

Blocking UDP port is quite uncommon.

There may be a lot of reasons, therefore the modem trace or capture.

From the board conf.

# Disable Duplicate Address Detection (DAD)
# due to not being properly implemented for offloaded interfaces.
CONFIG_NET_IPV6_NBR_CACHE=n
CONFIG_NET_IPV6_MLD=n

Not sure, if your SIM uses IPv6 instead of IPv4. There are several pretty nasty consequences, as that comment already points to. Here in Europe quite a lot is only supporting IPv4 and so are also many samples only support IPv4. Even if it turns out, that it is related to IPv6, I will not be of too much help, because my SIMs gets only IPv4 ;-). But then maybe someone from Nordic jumps in.

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Achim Kraus — Wed, 04 Jun 2025 07:44:27 GMT

[quote userid="132958" url="~/f/nordic-q-a/121809/help-with-coap-client-sample-on-nrf9160-dk-using-jio-nb-iot-sim/537983"]From what I understand, the nRF9151 is fully compatible with the nrf9160dk_nrf9160_ns build target, and no changes to the configuration are required for this sample. Please correct me if I'm wrong.[/quote]

You're wrong. The upwards compatibility is AFAIK only about the AT cmds.

Anyway, though zephyr is not only about the mcu or modem, it's about the board with the periphery, you should always use the specific board to build.

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Achim Kraus — Wed, 04 Jun 2025 07:42:00 GMT

west build -b nrf9151dk/nrf9151/ns --pristine -- -DCONFIG_COAP_SAMPLE_SERVER_HOSTNAME='"coap.me"' -DCONFIG_COAP_SAMPLE_RESOURCE='"hello"' -DSNIPPET="nrf91-modem-trace-uart" -DCONFIG_LTE_NETWORK_MODE_NBIOT=y

(you may skip the -DCONFIG_LTE_NETWORK_MODE_NBIOT=y, I just add this to force my modem in NB-IoT mode.)

devzone.nordicsemi.com/.../coap_2D00_nbiot.pcapng.gz

Edited: just in the case you're not common with using the modem trace and export capture in wireshark.

Modem Trace, see DevAcademy - Modem Trace

Export Captures, see Logs and IP Capturing ‐ How To Provide The Right Information - Wireshark.

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Arun_538 — Wed, 04 Jun 2025 07:29:14 GMT

I forgot to mention — I'm actually using the nRF9151 DK, not the nRF9160.

From what I understand, the nRF9151 is fully compatible with the nrf9160dk_nrf9160_ns build target, and no changes to the configuration are required for this sample. Please correct me if I'm wrong.

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Arun_538 — Wed, 04 Jun 2025 07:26:33 GMT

still facing

*** Booting nRF Connect SDK v2.9.1-60d0d6c8d42d ***
*** Using Zephyr OS v3.7.99-ca954a6216c9 ***
[00:00:00.389,739] <inf> coap_client_sample: The CoAP client sample started
[00:00:00.389,770] <inf> coap_client_sample: Bringing network interface up and connecting to the network
[00:00:00.723,083] <inf> coap_client_sample: Waiting for network connectivity
[00:01:16.345,245] <wrn> nrf_modem_lib_netif: No IPv4 address given by the network
[00:01:16.411,895] <inf> coap_client_sample: Network connectivity established
[00:01:16.616,424] <inf> coap_client_sample: IPv4 Address found 134.102.218.18
[00:01:16.616,729] <inf> coap_client_sample: Initializing CoAP client
[00:01:16.618,347] <err> coap_client_sample: Failed to send request: -114
[00:01:16.618,347] <err> coap_client_sample: periodic_coap_request_loop, error: -114
[00:01:16.618,347] <err> coap_client_sample: Fatal error! Rebooting the device*** Booting nRF Connect SDK v2.9.1-60d0d6c8d42d ***
*** Using Zephyr OS v3.7.99-ca954a6216c9 ***
[00:00:00.253,295] <inf> coap_client_sample: The CoAP client sample started
[00:00:00.253,326] <inf> coap_client_sample: Bringing network interface up and connecting to the network
[00:00:00.584,411] <inf> coap_client_sample: Waiting for network connectivity
[00:01:21.317,138] <wrn> nrf_modem_lib_netif: No IPv4 address given by the network
[00:01:21.388,763] <inf> coap_client_sample: Network connectivity established
[00:01:21.738,281] <inf> coap_client_sample: IPv4 Address found 134.102.218.18
[00:01:21.738,555] <inf> coap_client_sample: Initializing CoAP client
[00:01:21.740,173] <err> coap_client_sample: Failed to send request: -114
[00:01:21.740,203] <err> coap_client_sample: periodic_coap_request_loop, error: -114
[00:01:21.740,203] <err> coap_client_sample: Fatal error! Rebooting the device

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Achim Kraus — Wed, 04 Jun 2025 07:08:37 GMT

west build -d build_nrf9160dk_nrf9160_ns -b nrf9160dk/nrf9160/ns --pristine -- -DCONFIG_COAP_SAMPLE_SERVER_HOSTNAME='"coap.me"' -DCONFIG_COAP_SAMPLE_RESOURCE='"hello"' -DSNIPPET="nrf91-modem-trace-uart"

will enable the modem trace.

devzone.nordicsemi.com/.../coap.pcapng.gz

(My modem uses currently LTE-M, in my experience in Europe, there is no difference according UDP, except that LTE-M has a lower latency.)

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Arun_538 — Wed, 04 Jun 2025 07:04:05 GMT

Yes, I’m using NCS 2.9.1 with the sample located at:
nrf/samples/net/coap_client

I only modified these two Kconfig values:

CONFIG_COAP_SAMPLE_SERVER_HOSTNAME="coap.me"
CONFIG_COAP_SAMPLE_RESOURCE="hello"

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Arun_538 — Wed, 04 Jun 2025 06:59:04 GMT

Thank you. Yes DNS resolves correctly, and I get the IPv4 address for coap.me, but the CoAP GET request fails with error -114.

That’s why I suspect the issue may be that Jio’s NB-IoT network allows DNS (UDP port 53), but blocks CoAP (UDP port 5683) or general UDP traffic to public servers.

I'm looking forward to your updated sample with modem trace support — it will help confirm what's happening at the modem level.

Just to clarify, is this issue definitely due to my SIM/network, or is there still a chance it could be a configuration issue?

Please let me know once the updated sample is available.

Thanks again for your help!

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Achim Kraus — Wed, 04 Jun 2025 06:45:34 GMT

If DNS works (that works also over UDP), CoAP should work as well.

I will setup the sample to provide a modem trace, seems that the sample is not "up-to-date" for that.

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Achim Kraus — Wed, 04 Jun 2025 06:43:56 GMT

Your using NCS 2.9.1 and the "nrf/samples/net/coap_client"?

You only modified the COAP_SAMPLE_SERVER_HOSTNAME and COAP_SAMPLE_RESOURCE?

(CONFIG_LTE_AUTO_INIT_AND_CONNECT isn't longer valid for NCS 2.9.1).

build with:

west build -d build_nrf9160dk_nrf9160_ns -b nrf9160dk/nrf9160/ns --pristine -- -DCONFIG_COAP_SAMPLE_SERVER_HOSTNAME='"coap.me"' -DCONFIG_COAP_SAMPLE_RESOURCE='"hello"'

log:

*** Booting nRF Connect SDK v2.9.1-60d0d6c8d42d ***
*** Using Zephyr OS v3.7.99-ca954a6216c9 ***
[00:00:00.361,267] <inf> coap_client_sample: The CoAP client sample started
[00:00:00.361,297] <inf> coap_client_sample: Bringing network interface up and connecting to the network
[00:00:00.639,953] <inf> coap_client_sample: Waiting for network connectivity
[00:00:04.856,750] <inf> coap_client_sample: Network connectivity established
[00:00:11.097,595] <inf> coap_client_sample: Network connectivity lost
[00:00:12.389,495] <err> coap_client_sample: getaddrinfo, error: -11
[00:00:12.389,526] <err> coap_client_sample: Failed to resolve server name
[00:00:12.389,556] <err> coap_client_sample: periodic_coap_request_loop, error: -11
[00:00:12.389,556] <err> coap_client_sample: Fatal error! Rebooting the device.
*** Booting nRF Connect SDK v2.9.1-60d0d6c8d42d ***
*** Using Zephyr OS v3.7.99-ca954a6216c9 ***
[00:00:00.253,875] <inf> coap_client_sample: The CoAP client sample started
[00:00:00.253,906] <inf> coap_client_sample: Bringing network interface up and connecting to the network
[00:00:00.532,379] <inf> coap_client_sample: Waiting for network connectivity
[00:00:04.866,058] <inf> coap_client_sample: Network connectivity established
[00:00:12.886,718] <inf> coap_client_sample: Network connectivity lost
[00:00:15.669,952] <inf> coap_client_sample: Network connectivity established
[00:00:16.224,029] <inf> coap_client_sample: IPv4 Address found 134.102.218.18
[00:00:16.224,304] <inf> coap_client_sample: Initializing CoAP client
[00:00:16.225,921] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:16.312,255] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:00:21.267,181] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:22.056,579] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:00:26.308,471] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:26.887,603] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:00:31.349,761] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:31.965,087] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:00:36.391,082] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:37.008,239] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:00:41.432,403] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:42.005,462] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:00:46.473,693] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:47.044,525] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:00:51.515,014] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:52.085,845] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:00:56.556,335] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:00:58.556,243] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:01:01.597,656] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:01:02.214,294] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world
[00:01:06.638,977] <inf> coap_client_sample: CoAP GET request sent sent to coap.me, resource: hello
[00:01:07.635,589] <inf> coap_client_sample: CoAP response: code: 0x45, payload: world

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Arun_538 — Wed, 04 Jun 2025 03:53:47 GMT

Hi,

My setup:

LTE network registration is successful
DNS resolution of coap.me works
IPv4 address is found
But the CoAP request fails with error: -114 (ENETUNREACH)

Has anyone successfully sent UDP CoAP packets using any Indian NB-IoT SIM (Vodafone, BSNL, etc.)?

RE: Help with CoAP Client Sample on nRF9160 DK Using Jio NB-IoT SIM

Achim Kraus — Tue, 27 May 2025 15:55:36 GMT

Let me recommend:

First check, if the modem registers successful to a network, e.g. enable the modem trace and use the cellular monitor.

Does it register? If not, it's related to you SIM card and the available networks.

> Has anyone successfully used NB-IoT (especially with Jio SIM) to send CoAP requests over UDP?

Not with that SIM. With a couple of other SIMs, if there is a subscribed NB-IoT network reachable, it works. UDP is nothing special on that level. I use CoAP via cellular (nRF9160) for a couple of years. It's superior in terms of data-volume and energy, especially, if encryption is required, DTLS 1.2 CID does a good job (RFC9146, I'm one of the co-autors, so I'm biased).