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Contributor I

ARP problems after connection

Hey,

i am running an Aruba Mobility Controller based wireless network. I get reports from some users that their devices do not receive any ARP traffic after connecting to a wireless network, this includes the ARP replies from the router. This leads to some devices trying to reconnect to the network because they do not have a internet connection.

I can confirm this issue by looking at my own traffic after connecting to the network, it takes up to 45 seconds for the ARP replies to reach my device.

I have "Dynamic Multicast Optimization" enabled (threshold of 6), "Convert Broadcast ARP requests to unicast" is also enabled, "Drop Broadcast and Multicast" is disabled. I am running version 8.3.0.6.

Is this a know issue? Can it be fixed easily or do i have to investigate further?

Guru Elite

Re: ARP problems after connection

"Drop Broadcast and Unknown Multicast" should be enabled in most networks on all Virtual APs, because the level of brodcast traffic in networks can overwhelm unicast traffic and needs to be controlled.

 

Dynamic Multicast Optimization, in this scenario, typically does not play a part.


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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Contributor I

Re: ARP problems after connection

Thanks for your reply. I tried that option but that doesn't seem to fix the problem. In fact, it seems to make it worse, my laptop does not get any ARP replies at all after enabling that feature. I turned off "Drop Broadcast and Multicast" and "Convert Broadcast ARP requests to unicast" completely and now I am recieveing ARP replies again.

I still would like to use those features, so I would be glad if we could find a solution to this problem.

Guru Elite

Re: ARP problems after connection

You mentioned that users complain that they do not get ARP replies.  How do users know that?  How long has this been happening?  What non-default settings do you have on your mobility controller?


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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Contributor I

Re: ARP problems after connection

It got reported occasionally since we run the system. Recently it happened to me as well and I could verify that it is an ARP issue by looking at my traffic. Users experienced disconnects an “no internet connection” warnings.

What do you mean by “non-default settings” on the controller? I do the configuration manly via the web interface.

Guru Elite

Re: ARP problems after connection

Ok.

 

Are the client computers Windows machines?

 

Are you using encryption on that wireless network?

 


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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Contributor I

Re: ARP problems after connection

The issue has been observed on all kinds of devices, but mostly Android automatically disconnects if no ARP is recieved. I have confirmed it unsing Wireshart on macOS.

 

The network is secured using WPA2-Enterprise.

Guru Elite

Re: ARP problems after connection

How long has it been happening?  Have there been any changes on the network?


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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Contributor I

Re: ARP problems after connection

We have had issues regarding ARP for some time in the wifi, I cannot exactly specify when it started. At first i thought it might be our new core switch (Aruba 8320) which also is the gateway in the network, but the issue does not occur when connecting to the same network wired or via our old WiFi System.

Guru Elite

Re: ARP problems after connection

You should definitely open a TAC case in conjunction with this post to ensure someone can look at your configuration unredacted.


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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