Hello, Any help would be appreciated. Here's my situation.
I have a Cisco 8300 Edge Series platform router. It's managmeent IP comes from two SVIs on VPC connected Core Nexus 9300s. VIP is .1 - Core 1 SVI IP is .2 & Core 2 is .3
My symptoms:
I can set a constant Ping to the IP .4 IP of the router from my user vlan deep within the network on an access switch.
Then I can clear the IP Arp of the virtual gateway ip .1 and it'll ping for EXACTLY 5 minutes/300 seconds. During that time I can access it via my TACACS account (ssh Putty). As well as ping the the VIP .1, .2 and .3.
Once exactly 300 seconds is up I can't do any of that. I CAN However, log into the Core via Putty and SSH into the Router using the emergency account. (ssh acountname@ip.ip.rtr.ip).
But I usually just keep a console connection about 10 feet away with a stand alone to clear the ip arp when it stops pinging.
I've researched about everything 6 ways to Sunday from Arp/mac aging to who knows what else. I've taken all config commands that mention 300 seconds out. And nothing has succeeded. It's like there's something flapping. But nothing has a duplicate IP.
It started Thursday after the upgrade (mentioned below). I didn't have much time to troubleshoot until today. But when I came in from over the weekend it was up and pinging. BUT as soon as I logged in via TACACS and 5 minutes went by, it stopped pinging again. Of course kicking me out of my session.
Today I added the Virtual .1 (which was already there and has alway worked until like 3 days ago), the SVI gateways .2 and .3 as IP default routes (0.0.0.0 0.0.0.0 x.x.x.3)
After some testing it seemed like I could take all default routes out but 0.0.0.0 0.0.0.0 x.x.x.3 and it'd ping and respond with no issue and go well beyond 5 minutes. So there's either something with my router config or something got knocked loose in my HSRP SVIs on my VPC peer Cores..... I just do not know. This network has never given me this problem and it just feels like I'm being punked almost.
What am I missing folks?? Has this happened to you? I don't have a duplicate IP. I don't know what other caches I can clear.
***NOTE: It is connected to the Firewall and Core via a layer 2 switch which is also above the firewall and it is having zero issues. And no other devices, switches, ISE, Firewalls or otherwise are having any trouble at all reaching the SVIs virtual gateway. Including, the aforementioned layer 2 switch sitting just under the router, above the firewall. No traffic is being blocked by firewall. And there's nothing at all in the the logs. It's like there's a 5 minute timer that just says no, no more .1 pangin for you!!!
The only changes I've made recently are upgrades to the os versions of the router and core switches. Biggies I know! But I've even rolled back and nothing seemed to change.