Shelly Plus 1 (Gen 2) not discovered by Venus OS 3.70~58 — No CoAP packets received by GX

Beta testing Venus OS beta testing
1

Hi team,
I’m running into an issue with Shelly Plus 1 (Gen 2) devices on Venus OS 3.70~58 on an Ekrano GX, and I have packet-level evidence that the GX is not receiving any CoAP announcements from these devices.

Environment

  • Victron Ekrano GX

  • Venus OS v3.70~58 (beta)

  • Shelly Plus 1 (Gen 2) devices

  • Firmware: 1.7.1

  • Network setup:

    • All devices on same flat LAN, no VLANs

    • Peplink MAX BR1 Pro 5G as router (no IGMP snooping options, all traffic untagged)

    • GX is wired Ethernet

    • Shellys are on 2.4 GHz WiFi

    • Connectivity between GX ↔ Shelly (ping, HTTP UI, etc.) is fully working

Problem

  • Gen 2 Shellys never appear under Settings → I/O → Shelly Integration.

  • Gen 1 devices (e.g., RGBW2) appear normally.

  • Gen 2 devices are reachable (HTTP, ping).

  • After hours of testing, not a single CoAP or mDNS packet from the Gen 2 units reaches the GX.

Packet Capture Evidence

I installed tcpdump on the Ekrano GX and ran:

tcpdump -ni eth0 udp port 5683 or udp port 5353

Here is what I see:

:check_mark: Shelly Gen 1 RGBW2

Multicast traffic appears every ~10–20 seconds:

192.168.50.22.5683 > 224.0.1.187.5683
192.168.50.22.5353 > 224.0.0.251.5353
...

:cross_mark: Shelly Plus 1 (Gen 2)

No CoAP or mDNS packets observed at all:

tcpdump -ni eth0 host 192.168.50.31 and udp port 5683
0 packets captured

However, these Gen 2 devices answer pings consistently:

64 bytes from 192.168.50.31: ttl=255 time=5 ms

So IP-level connectivity is intact; the UDP multicast announcements seem completely absent.

Interpretation

Based on Victron’s documentation, Shelly discovery on GX relies on:

  • CoAP multicast → 224.0.1.187:5683

  • mDNS → 224.0.0.251:5353

It appears that the Shelly Plus 1 Gen 2 firmware (1.7.1) may not be sending the expected multicast traffic needed for GX discovery, or the GX is not listening for the new Gen2 protocol.

Given:

  • Gen 1 devices work immediately

  • Gen 2 devices send no multicast (confirmed via capture)

  • Flat LAN, no snooping, no filtering

  • TCP/IP connectivity is normal

  • Behavior is identical across multiple units

This looks like a Venus OS Shelly integration gap for Gen 2 devices or a Shelly Gen2 firmware issue relating to CoAP announcements.

Questions for the Victron team

  1. Does Venus OS 3.70 Shelly integration support Shelly Gen 2 (Plus) devices yet?

  2. Does the integration expect CoAP v1, and the Gen 2 devices use a different announcement protocol?

  3. Should Gen 2 devices appear automatically, or is extra configuration required?

  4. Is there a known compatibility issue with Shelly firmware 1.7.1?

Happy to run more captures or provide full pcap files if it helps.

Thanks,
Joe

2

Hi @joeAV541

Thanks for your question and the detailed investigation.

Answers to your questions:

  1. Does Venus OS 3.70 Shelly integration support Shelly Gen 2 (Plus) devices yet?
    Based on the Shelly documentation, Gen2 devices should be supported, but we have not verified this ourselves.
  2. Does the integration expect CoAP v1, and the Gen 2 devices use a different announcement protocol?
    No, the integration does not use CoAP. It uses mDNS for discovery and the RPC protocol over websockets for control. The integration is based on the aioshelly library.
  3. Should Gen 2 devices appear automatically, or is extra configuration required?
    As long as they can be discovered over mDNS and are not password protected, they should show up in the UI. But again, gen2 device support is not tested. I’ll try to get hold of a gen2 device so we can test it.
  4. Is there a known compatibility issue with Shelly firmware 1.7.1?
    Not that we are aware of.

And are you sure you’re probing correctly? This command does not seem to filter for port 5353:

tcpdump -ni eth0 host 192.168.50.31 and udp port 5683
0 packets captured

It’s also surprising for me that a gen1 seems to work properly with the Shelly integration. To my knowledge, gen1 devices do not support the RPC protocol used in the integration.

Regards,
Rein.

3

Thanks, Rein, for the reply. I have root caused my issue and the issue was me :). The Shelly team help me narrow my issues down and get the Shelly Plus 1 (Gen 2) to integrated into Venus OS 3.70~58. There were two discoveries I found along the way.

  1. Gen 2 Shelly and Gen 1 implemented mDNS differently. Gen 1 provides unsolicited mDNS broadcasts every few minutes. Gen2 only responds to mDNS queries. And since the GX only polls devices every 15 minutes, I never captured a query. When I captured traffic over a much longer period, I saw the Gen 2 devices responding.
  2. I was enabling authentication after about 10 minutes of initializing Gen 2 devices. Although Gen 2 devices responds properly to mDNS queries when authentication is enabled, the Venos OS 3.7 doesn’t yet handle authenticated devices.

Consider this closed! Gen 2 does integrate into Venus OS 3.7. Thank you.

root@ekrano:~# tcpdump -ni eth0 ‘udp port 5353 and ((src host 192.168.50.12 and dst host 224.0.0.251) or src host 192.168.50.24)’ | grep -E ‘_shelly\.|shellyplus1-|_http\._tcp’

tcpdump: verbose output suppressed, use -v[v]… for full protocol decode

listening on eth0, link-type EN10MB (Ethernet), snapshot length 262144 bytes

20:39:40.955154 IP 192.168.50.12.5353 > 224.0.0.251.5353: 0 PTR (QM)? _shelly._tcp.local. (36)

20:39:41.168091 IP 192.168.50.24.5353 > 224.0.0.251.5353: 0*- [0q] 2/0/12 PTR Van Lights._shelly._tcp.local., PTR shellyplus1-cc7b5c0d35d0._shelly._tcp.local. (426)

20:53:44.836972 IP 192.168.50.12.5353 > 224.0.0.251.5353: 0 PTR (QM)? _shelly._tcp.local. (36)

20:53:45.043279 IP 192.168.50.24.5353 > 224.0.0.251.5353: 0*- [0q] 2/0/12 PTR Van Lights._shelly._tcp.local., PTR shellyplus1-cc7b5c0d35d0._shelly._tcp.local. (426)

21:07:48.748788 IP 192.168.50.12.5353 > 224.0.0.251.5353: 0 PTR (QM)? _shelly._tcp.local. (36)

21:07:48.845236 IP 192.168.50.24.5353 > 224.0.0.251.5353: 0*- [0q] 2/0/12 PTR Van Lights._shelly._tcp.local., PTR shellyplus1-cc7b5c0d35d0._shelly._tcp.local. (426)

21:21:52.600351 IP 192.168.50.12.5353 > 224.0.0.251.5353: 0 PTR (QM)? _shelly._tcp.local. (36)

21:21:52.779107 IP 192.168.50.24.5353 > 224.0.0.251.5353: 0*- [0q] 2/0/12 PTR Van Lights._shelly._tcp.local., PTR shellyplus1-cc7b5c0d35d0._shelly._tcp.local. (426)

21:35:56.477038 IP 192.168.50.12.5353 > 224.0.0.251.5353: 0 PTR (QM)? _shelly._tcp.local. (36)

21:35:56.673459 IP 192.168.50.24.5353 > 224.0.0.251.5353: 0*- [0q] 2/0/12 PTR Van Lights._shelly._tcp.local., PTR shellyplus1-cc7b5c0d35d0._shelly._tcp.local. (426)

4

Hi @joeAV541,

Great, thanks for the insights!
And indeed, venus OS 3.70 beta does not support authentication yet, but it is on the list.