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Smart Hub 7 Plus: IPv6 Router Advertisements not emitted after reboot

patters
Investigator
Investigator

‎04-08-2026 02:54 PM - edited ‎04-08-2026 03:05 PM

Expected behaviour:

In IPv6 Stateless mode, the Hub should advertise the delegated LAN prefix using IPv6 Router Advertisements (RAs), allowing LAN devices to automatically configure global IPv6 addresses.

Observed behaviour:

The Hub shows:

  • IPv6 status: Enabled
  • IPv6 LAN prefix/address present

but does not emit Router Advertisements.

Packet capture on the NAS:

tcpdump -i eth0 -nn 'icmp6 and ip6[40] == 134'

shows no Router Advertisements.

The result is that LAN devices only have link-local addresses:

fe80::/10

(which are generated independently of RAs), but do not receive a globally routable IPv6 address.

A workaround I found:

  • Hub Manager → Advanced Settings → IPv6 → Configuration → Reset to default

Or if that doesn't make a change:

  • Toggle IPv6 allocation mode (for example Stateless → Off → Stateless)
  • Save/apply

After this, the Hub starts sending RAs again on a 1-9 minute interval and the NAS receives a global address, for example:

2a00:1234:5678:9abc:0211:32ff:fe2d:750f

However, after a reboot the Smart Hub will pick up new IPv6 addressing and will subsequently fail to emit any RAs.

 

Firmware version: r4.27.1-R-1862254-PROD-84001

App version: 3.14.5

0 Helpful
13 REPLIES 13
patters
Investigator
Investigator
In response to bobpullen

‎13-08-2026 10:07 AM - edited ‎13-08-2026 10:08 AM

Not all devices are equal. I think most operating systems will send an RS (Router Solicitation) when an interface comes up, which would prompt the RA (Router Advertisement)  in response. In my case, when I'm away from home, the only LAN device that's powered on is my NAS. The Synology operating system, for some reason, does not send an RS even after a reboot, it merely waits for an unsolicited RA which, according to ChatGPT, is a compliant IPv6 implementation. So to fully emulate my setup you'd have to instruct your test machines not to issue Router Solicitations. The router must emit those unsolicited RAs to be compliant with the IPv6 spec. In my case it does not. I return home tonight so perhaps I'll get some time tomorrow to perform the reset.

Huggons1
Established Contributor
Established Contributor
In response to patters

‎13-08-2026 12:50 PM

Do you mean that you restarted it remotely using the EE app? If so you must be using an older app version, as the last two app updates removed this feature 

0 Helpful
bobpullen
Star Contributor
Star Contributor
In response to Huggons1

‎13-08-2026 03:15 PM

@Huggons1 - it was restarted remotely via the Hub manager according to an earlier reply.

@patters - thanks, that puts a slightly different angle on the issue. That said...

So to fully emulate my setup you'd have to instruct your test machines not to issue Router Solicitations. 

Removed all LAN devices apart from a single wired laptop and fully disabled WiFi in the Hub Manager. Disabled IPv6 entirely on the laptop and confirmed it was not assigned any IPv6 addresses: -

~$ ip -6 addr show dev enp0s31f6
~$

Restarted the router via the physical on/off switch and fired up a capture to check for both RS and RA packets. As expected, no RS traffic because IPv6 was disabled on the laptop. What you can see though are unsolicited RA packets at an interval of roughly 5 minutes (which I believe is the maximum defined in standards): -

~$ sudo tcpdump -n -tttt -i enp0s31f6 icmp6 and
'(ip6[40] == 133 or ip6[40] == 134)'
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on enp0s31f6, link-type EN10MB (Ethernet), snapshot length
262144 bytes
2026-08-13 14:29:18.130543 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 64
2026-08-13 14:29:24.755126 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:29:34.814791 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:29:37.571909 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:29:45.387801 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:29:46.965849 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:35:50.402629 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:39:47.261558 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:43:48.055403 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:48:34.961326 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
2026-08-13 14:52:00.188077 IP6 fe80::628d:26ff:fed1:5378 > ff02::1:
ICMP6, router advertisement, length 120
0 Helpful
patters
Investigator
Investigator

‎16-08-2026 11:24 PM - edited ‎16-08-2026 11:25 PM

I have spent several hours this evening performing a factory reset, and reconfiguring all my wifi settings as I had before. Unfortunately it hasn't made the slightest difference. My router wasn't emiting RAs at all until clicked to reset all IPv6 settings in Hub Manager. I waited around half an hour with a tcpdump open and nothing. My work and personal MacBooks were not getting routable IPv6 addresses (only the link local ones), despite emitting RS requests when I cycled their wifi interfaces. The moment I clicked to reset IPv6 on the router the tcpdump lit up and they got IPv6 GUA addresses. This firmware is certainly broken.

In case it's relevant, I have my main SSID set to WPA3 Personal, and a Compatibility SSID set to WPA2 Personal.

0 Helpful