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CraftBeerCFO
Trending Lyricist I
June 17, 2025
Answered

Sub 4 Loses Connection

  • June 17, 2025
  • 13 replies
  • 659 views

I have a sub 4 that’s paired with an arc ultra that keep losing connection.  The sub will connect and play with the arc ultra for a couple of minutes then drop the connection.  Sonos pointed fingers at my router, a Cisco RV340.  I engaged Cisco support and they cannot find any reason to sell me a new router, as suggested by Sonos.  Everything else in the house works fine on the same network.  Is anyone else having an issue with the sub 4 staying connected?  If so, what was the fix?  Any insight or suggestions would be greatly appreciated.  

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Best answer by Corry P

Hi ​@CraftBeerCFO 

The router needs to support DHCP Proxy - though, I don’t think this is something that tends to get advertised. Most routers do support it - I only know of Cisco and Asus not doing so (though I believe with Asus it can be worked-around).

You can see our hardware incompatibility list here: Incompatible network hardware. Cisco is listed there, but only multiple ethernet connections to Sonos is listed as an issue - possibly because the workaround for your issue is to use a single ethernet connection.

Incidentally, the last person I help that had this issue was able to bypass it after disabling QoS (Quality of Service) functionality in their router’s setting, though that was with Asus - perhaps you will have the same luck? I hope so.

I hope this helps.

13 replies

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PiotrU
Lyricist I
July 5, 2025

Hi all! Same story here. Sub4 looses connection with Arc Ultra on Cisco-built network. I do have an additionall insight - sub4 looses connection only when added to arc ultra. It looks like the above mentioned bonding (?) with arc disrupts sub4 connection.

 

Here’s how I found it out:

  • factory reset of sub4
  • connect it to the Sonos app, but do not connect to arc ultra
  • —— at this stage sub4 is visible in WiFi network. It has a stable connection, no issue with dhcp.
  • sub4 is shown in the app as unbound to any room. 
  • initiate connection to arc4. It connects successfully but at this momentvthe apps stops seeing the sub4 :(
  • after a few minutes, sub4 also drops from dhcp - sleep mode?

 

any suggestions are more than welcomed!

 

thanks!

piotr

    nik9669a
    Senior Virtuoso
    July 5, 2025

    Hi all! Same story here. Sub4 looses connection with Arc Ultra on Cisco-built network. I do have an additionall insight - sub4 looses connection only when added to arc ultra. It looks like the above mentioned bonding (?) with arc disrupts sub4 connection.

     

    any suggestions are more than welcomed!

     

    thanks!

    piotr


    Have you tried what ​@Corry P suggested above? 

      craigski
      Local Superstar
      July 5, 2025

      any suggestions are more than welcomed!

       

      This issue is probably due to the way your Cisco network is handling ARP. As you have seen before the Sub is bonded it gets an IP address using its own MAC address, all OK

      When the Sub is bonded to the Arc, it will use the Arc Ultra MAC address. The Cisco will then see this as a potential ‘ARP Spoof’ as the Arc Ultra and Sub will have same MAC address but different IPs, and block, you will need to configure the Cisco to allow these ARP requests from the the Arc Ultra, and not block them.

      Your (Enterprise?) Cisco network may not be suitable for a consumer/home environment, unless it is configured appropriately.

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