Problem: PaloAlto firewall is dropping packets in small bursts of some seconds, and sometimes it drops TCP connections. It only happens on HA clusters on interfaces in active/passive (fail over) mode.
Solution: disable the following check box in the Ethernet interface Advanced – LLDP settings: “Enable in HA Passive State”
Discussion: Palo Alto uses only one MAC address for both machines of an HA cluster. The passive box sends LLDP packets using this MAC address. The switch learns this MAC address and sends the traffic to the passive node until the active node sends new packets. The passive node should never send packets with the MAC address of the active node, and should have its own MAC address for LLDP and possibly other services.
Version: PaloAlto current version of Nov 2016, connected to a Cisco Catalyst 6500
Problem: Cisco ASR router is loosing connectivity to its directly attached Ethernet neighbors. In this situation interface status is still up, packets are going in and out on both ends, even IPv6 was still working. The actual problem was that the Cisco ASR was ignoring all ARP responses from its neighbors and the ARP table to this interface was empty. Later the same happened on a second interface.
A temporary work around was to reboot the router.
Solution: Cisco support suggested a software upgrade, even though the software was only some weeks old. After the software upgrade the error didn’t happen again until now.
The old IOS version was: asr1001x-universalk9.03.16.03.S.155-3.S3-ext.SPA.bin
The new IOS version is: asr1001x-universalk9.03.16.04a.S.155-3.S4a-ext.SPA.bin
The only fix that possibly fits to the problem is:
“A remote attacker can cause an interface wedge and an eventual denial of service condition”
What’s an “interface wedge”. Cisco bug reports were more precise years ago.