AX88U v386.2_6 - Guest WIFI SSID breaks WAN connectivity

[Phk]

Hello everyone,

Finally, I'm able to reproduce a bug that pretty much happens in every 2021 release for AX88u. I wasn't able to pinpoint it, so I was using an old version (from more or less one year ago).

I have an SSID for 2.4Ghz and 5.0Ghz with the same name, lets say "MYWIFI", without WIFI6 enabled and no Smart Connect enabled either.
Then, I have a guest network for N clients "MYWIFI_Guest_N" and another for AC clients "MYWIFI_Guest_AC", both with intranet access blocked (to use with pretty much every tablet, smart device, etc).
This setup does not survive reboots..

TL;DR

The setup:

• RT-AX88u
• Merlin-WRT version 386.2_6
• One SSID name for 2.4 and same name for 5.0
• no Smart Connect or Wifi6
• One guest Wi-Fi for N
• One guest Wi-Fi for AC

The issue:

• When the Router reboots normally or because of power loss, everything works OK except for the Guest networks. No clients can obtain IP address on the Guest networks after a normal reboot.
• When this happens, if you go to Web UI and change anything, the whole WAN connectivity gets broken, even for wired clients.

The dirty fix:

1. Disable Guest networks
2. Reboot
3. Manually enable Guest networks again, and apply
4. Everything works.

The logs:

admin@RT-AX88U:/tmp/home/root# grep -n "Jun 10 18:39:" /jffs/syslog.log-1
494:Jun 10 18:39:39 kernel: wfd_unregisterdevice Successfully unregistered ifidx 1 wfd_idx 1
495:Jun 10 18:39:41 kernel: wfd_unregisterdevice Successfully unregistered ifidx 1 wfd_idx 0
496:Jun 10 18:39:41 kernel: wfd_registerdevice Successfully registered dev wl0.1 ifidx 1 wfd_idx 0
497:Jun 10 18:39:41 kernel: Register interface [wl0.1]  MAC: 04:d9:f5:fa:e0:a1
498:Jun 10 18:39:41 kernel: IGMP Query send failed
499:Jun 10 18:39:41 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
500:Jun 10 18:39:41 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
501:Jun 10 18:39:42 kernel: FPM Pool 1: invalid token 0x20a60000 freed
502:Jun 10 18:39:42 kernel: wfd_registerdevice Successfully registered dev wl1.1 ifidx 1 wfd_idx 1
503:Jun 10 18:39:42 kernel: Register interface [wl1.1]  MAC: 04:d9:f5:fa:e0:a5
504:Jun 10 18:39:42 kernel: IGMP Query send failed
505:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
506:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
507:Jun 10 18:39:42 kernel: FPM Pool 0: invalid token 0x00bb8000 freed
508:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
509:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
510:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
511:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
512:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
513:Jun 10 18:39:42 kernel: netdev path : eth6.0 -> eth6
514:Jun 10 18:39:42 kernel: BCMVLAN : eth6 mode was set to RG
515:Jun 10 18:39:42 kernel: netdev path : eth6.501 -> eth6
516:Jun 10 18:39:42 kernel: BCMVLAN : eth6 mode was set to RG
517:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
518:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
519:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
520:Jun 10 18:39:42 kernel: netdev path : eth7.0 -> eth7
521:Jun 10 18:39:42 kernel: BCMVLAN : eth7 mode was set to RG
522:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
523:Jun 10 18:39:42 kernel: netdev path : eth7.501 -> eth7
524:Jun 10 18:39:42 kernel: BCMVLAN : eth7 mode was set to RG
525:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m
526:Jun 10 18:39:42 kernel: ^[[0;33;41m[ERROR mcast] bcm_mcast_netlink_process_snoop_cfg,884: interface 34 could not be found^[[0m

When the router reboots and Guest networks are broken, if you touch any config in the Web UI, the router can't even ping 8.8.8.8. I think the routing table gets screwed because some interface naming gets changes. I have syslog full of "interface 34 cannot be found" errors, it seems to be an interface name mismatch after normal booting, which then messes everything up after changing anything.

Tell me if you need other tests or logs.

Cheers,
Phk

 

[L&LD]

Get your router/network to a good/known state first.

Fully Reset Router and Network

Best Practice Update/Setup Router/AiMesh Node(s) 2021


If you haven't performed the (needed/required) steps above, you are chasing your tail.

 

[Phk]

Get your router/network to a good/known state first.

Fully Reset Router and Network

Best Practice Update/Setup Router/AiMesh Node(s) 2021


If you haven't performed the (needed/required) steps above, you are chasing your tail.

Hello again,

You are right, I've done a clean install first, just like referred in the link you shared. Thank you, saved.

The issue "changed" but there is still a bug. So, let me detail the steps:

I've configured the basic wifi 2.4 and 5g SSID with smart connect, and then two guest networks: One for 2.4g and another for 5g, both without intranet access (the main purpose for this setup).
After I've set things up, everything was OK. After I rebooted, the 2.4g Guest Network would not be able to acquire IP addresses, and I have this in the logs:

Jul 17 16:50:40 dnsmasq-dhcp[3142]: no address range available for DHCP request via br1
Jul 17 16:50:41 dnsmasq-dhcp[3142]: no address range available for DHCP request via br1
Jul 17 16:50:41 dnsmasq-dhcp[3142]: no address range available for DHCP request via br1
Jul 17 16:50:41 dnsmasq-dhcp[3142]: no address range available for DHCP request via br1

Hundreds and hundreds of these lines.

So I rebooted again, same problem. Manually disabling and enabling the 2.4g guest network solved the issue (just like in this thread's opening post).
However, using the second column guest (2) instead of the first column (same as the 5g below) seemed to fix the issue.

So, using the 2nd guest slot for the 2.4G and the 1st guest slot for the 5G seemed to overcome the DHCP problem.

Feel free to ask for any logs or tests; I may take a while to get the outputs, but I'll do it as soon as I can.

Cheers