Palo Windows ARP Issue - Windows Hosts Not Installing ARP info

NSutfin — Thu, 30 Apr 2026 20:31:15 GMT

Hello,

We have random issue with Windows 11 Enterprise ( 10.0.26200) hosts not installing ARP reply from a stack of PAs running 10.2.7-h8.

I have captured the traffic with the (non ip) filter and I can see the ARP requests and the replys. The hosts are sourcing DHCP from a PA interface with standard options for mask, default gateway and domain .

The host will get an IPaddress and the palo will show the hosts arp entry. Additionally, if you clear the ARP entry on the FW, it will refresh with the same info. The PCAP shows the windows host hammering away with ARP requests for the gateway and the FW sending ARP replys. I can take another host , plug into the same port and it works just fine. Everything points to the Windows machine.

Has anyone else seen this?

Thanks,

Nathan

Re: Palo Windows ARP Issue - Windows Hosts Not Installing ARP info

JayGolf — Thu, 07 May 2026 01:03:17 GMT

Hi @NSutfin ,

Can you run a capture on the affected windows boxes to see if the ARP responses are hitting the NIC? If you see ARP hitting and the host still doesn't install the gateway MAC, It strongly suggests a local stack issue.

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Palo Windows ARP Issue - Windows Hosts Not Installing ARP info

Re: Palo Windows ARP Issue - Windows Hosts Not Installing ARP info