Disable IGMP Snooping on AX88u

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Soul_

Occasional Visitor
How do I disable IGMP Snooping on Asus AX88U? I have it disabled in:
  • Wireless professional settings,
  • and 'Multicast Routing' is disabled in IPTV settings as well
However, in Wireshark, I can clearly see the LAN Gateway IP (which sits on AX88U) generating IGMPv3 Membership queries.

Is there no way to disable IGMP snooping on these devices?
 

ColinTaylor

Part of the Furniture
Multicast Routing and IGMP Snooping are two different things. Neither stop IGMP traffic on the LAN. If you're seeing IGMP traffic originating from the router that you don't want you need to stop the process that's generating it.
 

Soul_

Occasional Visitor
Multicast Routing and IGMP Snooping are two different things. Neither stop IGMP traffic on the LAN. If you're seeing IGMP traffic originating from the router that you don't want you need to stop the process that's generating it.

I do understand that IGMP snooping and Multicast routing a two different things, I am a CCNP. The reason I mentioned it, is because older routers had IGMP option in IPTV, and this one only has Multicast routing, so I just mentioned it before anyone asks.

If you read my question again, the IGMP traffic is originating from the router's L3 interface on the LAN segment. Why is it originating and how can I stop it?

As in my question, the IGMP membership query, which is what triggers IGMP responses, is being generated by the AX88U router's L3 interface. So it is not some process generating and I am looking for the router to block it, it is being generated by the router and I would like the router to stop generating IGMP membership queries.
 
Last edited:

ColinTaylor

Part of the Furniture
Yes I read your question, you asked "How do I disable IGMP Snooping". That is not the same as "Why is it originating and how can I stop it". To stop the IGMP traffic you need to identify the process generating it. I don't know what that is on your router. Does Wireshark not give any clues as to the purpose of the traffic?
 

Soul_

Occasional Visitor
Yes I read your question, you asked "How do I disable IGMP Snooping". That is not the same as "Why is it originating and how can I stop it". To stop the IGMP traffic you need to identify the process generating it. I don't know what that is on your router. Does Wireshark not give any clues as to the purpose of the traffic?
So did you completely miss the part where I said,”I can clearly see the LAN Gateway IP (which sits on AX88U) generating IGMPv3 Membership queries.”?

Wireshark tells us which frames are being communicated, their purpose is identified with reason. igmp membership queries are typically generated by routing interfaces which have igmp snooping enabled.

My router is bone stock with Merlin latest firmware. And I have no idea why is it triggering igmp queries when snooping is disabled.

Sorry if I was a bit direct, but this is quite annoying. Back to my question, I would like to disable igmp snooping on this device which it clearly is not.
 
Last edited:

ColinTaylor

Part of the Furniture
The absence of this option on the HND routers has been discussed in the past. IIRC Merlin said it is not present any more because changing it would create problems with other parts of the Asus/Broadcom code.

You could try this and see what effect it has:
Code:
echo 0 > /sys/class/net/br0/bridge/multicast_snooping
 

Soul_

Occasional Visitor
Sorry, where do I execute it? Right on the SSH? or is there a special "conf t" mode that I have to enable in there?

I got this result:
/tmp/home/root# echo 0 > /sys/class/net/br0/bridge/multicast_snooping
-sh: can't create /sys/class/net/br0/bridge/multicast_snooping: Permission denied
 

ColinTaylor

Part of the Furniture
Yes, just SSH into the router and issue it from the command line. It will only be a temporary change until you reboot the router.
 

SomeWhereOverTheRainBow

Very Senior Member
Sorry, where do I execute it? Right on the SSH? or is there a special "conf t" mode that I have to enable in there?

I got this result:
/tmp/home/root# echo 0 > /sys/class/net/br0/bridge/multicast_snooping
-sh: can't create /sys/class/net/br0/bridge/multicast_snooping: Permission denied
Right on ssh.
 

Soul_

Occasional Visitor
Hmm... I logged in with admin rights from root, but it told me to piss off. I wonder if the router is just mad at me at this point.
 

ColinTaylor

Part of the Furniture
Your router has a much later kernel than mine so things might be different for you. See if you can find it:
Code:
find / -name multicast_snooping
 

Soul_

Occasional Visitor
Nothing showed up. /sad

/tmp/home/root# find / -name multicast_snooping
/tmp/home/root#
 

Soul_

Occasional Visitor
Your router has a much later kernel than mine so things might be different for you. See if you can find it:
Code:
find / -name multicast_snooping

this is what I found for multicast:

/tmp/home/root# find / -name *multicast*
/sys/devices/virtual/net/spu_us_dummy/statistics/multicast
/sys/devices/virtual/net/ip6tnl0/statistics/multicast
/sys/devices/virtual/net/bcmswlpbk0/statistics/multicast
/sys/devices/virtual/net/dpsta/statistics/multicast
/sys/devices/virtual/net/bcmsw/statistics/multicast
/sys/devices/virtual/net/bond1/statistics/multicast
/sys/devices/virtual/net/bond0/statistics/multicast
/sys/devices/virtual/net/ifb1/statistics/multicast
/sys/devices/virtual/net/ifb0/statistics/multicast
/sys/devices/virtual/net/imq0/statistics/multicast
/sys/devices/virtual/net/imq2/statistics/multicast
/sys/devices/virtual/net/imq1/statistics/multicast
/sys/devices/virtual/net/eth1/statistics/multicast
/sys/devices/virtual/net/eth0/statistics/multicast
/sys/devices/virtual/net/eth2/statistics/multicast
/sys/devices/virtual/net/eth4/statistics/multicast
/sys/devices/virtual/net/eth3/statistics/multicast
/sys/devices/virtual/net/eth5/statistics/multicast
/sys/devices/virtual/net/eth7/statistics/multicast
/sys/devices/virtual/net/eth6/statistics/multicast
/sys/devices/virtual/net/sit0/statistics/multicast
/sys/devices/virtual/net/lo/statistics/multicast
/sys/devices/virtual/net/br0/statistics/multicast (Maybe
this is what we need?)
/sys/devices/virtual/net/spu_ds_dummy/statistics/multicast
 

ColinTaylor

Part of the Furniture
Have a look at this thread. Although that discussion was regarding a problem with an IPTV service it does mention that the snooping/proxying is being handled by a process called mcpd. If your router uses the same process you could try killing it and seeing if your IGMP queries stop.
Code:
killall mcpd
 

Soul_

Occasional Visitor
Have a look at this thread. Although that discussion was regarding a problem with an IPTV service it does mention that the snooping/proxying is being handled by a process called mcpd. If your router uses the same process you could try killing it and seeing if your IGMP queries stop.
Code:
killall mcpd

That did it. The moment I ran the command, IGMP membership queries stopped. I wish this could be built into a small toggle switch in IPTV GUI.
 

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