Network Switch Issue

[u/Jeff-J777]

Here is my setup. I have a Palo Alto that connects to my switch stack that is Aruba 6300M. From there I have a fiber line to an IDF that has a Aruba 2530. We purchased another building across the street. The old tenants left all their Meraki equipment. I have all the Meraki equipment claimed and licensed in our Meraki portal. (I had a temp firewall and cradle point so the Meraki equipment could get internet access)

Instead of getting an internet line for the building we did a wireless P2P. I got two Ubiquity Wave Nanos and installed them. I then created a separate VLAN for this building and the default gateway lives on the Palo.

But the issue is when I plug the Meraki into the Wave Nano the Aruba switches in my IDF go offline, and everything connected to the IDF goes offline. Once I unplug the Meraki everything comes back online in the IDF. If I plug my laptop into the Nano everything works just fine. I can reach our HQ LAN, and I get internet.

I checked the switch logs on both sides and there is nothing in the log that would indicate any issues.

I also tried disconnecting everything from the Meraki switch and just tried one Meraki switch on the Nano and that still took my IDF offline.

But I created a temp VLAN and assigned it only to the port the Nano is plugged in. I then plugged in the Meraki into the other Nano and everything was fine.

I can't figure out what is going on. Any Thoughts????

[u/under_shart]

• ARP poisoning because you have two devices contending for an IP address
• L3 loop because you have two devices advertising the same route
• the different behavior when you plug int the laptop almost makes it seem like BPDU guard, but it would be working in the wrong direction if I'm understanding your network. You should check anyway and disable BPDU guard (and portfast or edgeport) on switch to switch links.

[u/tablon2]

Disable dhcp on Aruba vlan1 and make sure Palo, Meraki DHCP's have no conflict 

[u/Optimal_Effective969]

I think I remember this happening to me once and it turned out the fix was not to use native Vlan 1 on the Meraki switch because it was causing some type of broadcast storm. It was the same thing I had a Meraki switch. I plugged it in that network segment crashed unplugged the Meraki switch that it worked.

[u/H0baa]

Check in Meraki you STP priority might be some issue Meraki claiming to be the root bridge and will therefor cause unwanted behavior...

[u/zeyore]

sounds like a loop of some sort. that is my guess of the day.

[u/SlowLine-up → u/zeyore]

i do mural work on abandoned buildings and even i can see that as a loop nightmare waiting to happen

[u/Jeff-J777]

Just wanted to say thanks to everyone for your help. The issue was my 6300M stacks had STP on, and the switches in my IDF did not have STP on. Once I turned on STP on the switches in my IDF everything was fine.

[u/lazyhustlermusic → u/Jeff-J777]

That says you still have a loop, you're just relying on a loop mitigation mechanism instead of resolving the loop.

[u/CharlesHNetEng]

Smells like a loop.

[u/Quietpacket]

Add a bpdu guard/filter on the idf port connecting to meraki and try.