HA path monitoring in virtual wire

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HA path monitoring in virtual wire

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I've seen a couple answers here about using Path Monitoring in Virtual Wire. They say that one must use an IP address within the Virtual Wire subnet as the source address. OK, I get that. What I don't get is how to configure such an address. I don't see a way to add an address to a vwire interface. I've tried creating a loopback with no good result. Also gave vlan a shot, but that didn't look promising either. Thanks for any help.


L4 Transporter

Device -> High Availability -> Path Monitoring -> Path Group -> Add Virtual Wire has the option to add Source and Destination address. I am also working on similar monitoring where I would like to monitor device beyond connected device. I am still not sure how the routing would though. I have a case open with support with not much progress.

L5 Sessionator

How about configuring a L3 interface on PA and connecting it to the network providing a reachability to the Monitored Dest.

vwaghmar :

Excerpt from Admin guide : 5.0

Source IP—For virtual wire and VLAN interfaces, enter the source IP address used in the probe packets sent to the next-hop router (Destination IP address). The local router must be able to route the address to the fire­wall. The source IP address for path groups associated with virtual routers will be automatically configured as the interface IP address that is indi­cated in the route table as the egress interface for the specified destination IP address.

: L3 interface configuration is what suggested by our SE. The support talked about having src and dst ip in the subnet. That doesn't make any sense when you want to monitor devices beyond connected one. Have you tried this by yourself? Unfortunately I don't have an environment to play with and before touching the production devices, I wanted to make sure that I can plan ready for configuration and testing. I am running 4.x code. Do I need to have a combination of virtual wire and virtual router in the path monitoring config? Can you provide me more details?

Here is what my scenario is (apologies @gmparis for hijacking thread). Internet -> Internet router -> public switch -> Untrust firewall -> Untrust PAN -> Trust PAN -> DMZ switch. I can monitor dmz switch and trust interface of firewall using link monitoring and is working fine. I want to monitor the untrust firewall to pub switch connectivity. Here is what I understood.

- Connect new interface on PAN to dmz switch

- Configure L3 interface with trust side subnet of firewall

- Configure path monitoring with newly added interface? How do I add destination ip? I dont see any option to use single interface under path monitoring.

No problem about the hijacking, @vwaghmar. Thanks for answering my question. I was trying to test the path monitoring using ping before configuring it into HA. That apparently can't be made to work, but isn't necessary. Just putting the source address into the vwire path monitoring config is all that's needed. I was making it harder than it had to be.

Good luck with your layer-3 issue.

- Glad to know that it helped. I hope I will get answer for my questio as well. I am waiting for suggestions from for my testing. Till then I would continue to use your thread Smiley Happy

L2 Linker

Hi all

I'll join this thread cause this is exactly what I'm looking for.


I need to monitor HSRP address of routers because If outside interface goes down on cisco ASA, ASAs will switchover and PANs not.

Do I realy need to create seperate L3 interface just for this purpose? If yes I think that it will be easier to create L3 interfaces on PAN.



- Looks like we are in the same boat. The ASA failover does not trigger PA failover. Creating a separate L3 interface for monitoring is what suggested by our SE. Here is what I had tried over the last weekend but did not get satisfactory results due to ASA issues in our environment.

- Connect an interface from PAN to LAN switch

- Configure interface in L3 mode. I am assuming that PAN trust/inside is connected to a L3 switch having default gateway as ASA

- Configure new zone

- Configure new virtual router. I preferred to create new as the purpose was to use it purely for HA path monitoring. My PAN anyways configured in vWire mode

- Ping destination using src ping on PAN. Please note that somehow I was not able to ping ASA untrust from inside/trust. I am not sure if that is the feature in ASA but I did not have time to work on it. If you know how then please let me know. ASA egress IP is reachable from public

- Configure path monitoring with type as "virtual router". Configure destination address and select the virtual router with proper routing

- Check path monitoring status from cli # show high-availability path-monitoring

pan(active)> show high-availability path-monitoring


total paths monitored :                         1

interval to send ICMP probe packets :           200 ms

last N probes to determine path availability :  10

hold time to send probe packets :               60000 ms

  (after device becomes active)


name/type                        destination     succ/total rtt min/max/avg (ms)


ha-monitor-vrouter/virtual-router <destination ip>    10/10      0.80/1.04/0.88


My failover scenario worked fine after shutting down the ASA untrust link. I however had issues later when Active PAN become Primary again. I will be trying the same thing with Juniper firewalls again over coming weekend. If you manage to test in the meanwhile then please share the results.

thx vwaghmar for your answer.

as I remember you can't ping outside interface of ASA from inside Smiley Happy  so don't bother. Maybe if you change "management-interface" for outside (which is not recomended) but it is not easily done casue managemnt-interface can't be the one with the lowest "security-level".

Unfortunately I dont have 2 ASAs in my lab to test all interesting parts.

My first question is whether PAN tranfers traffic in vwire when it is in passive mode? It is fundamental question cause
If the answer is yes then it is no use of creating L3 interface for path monitoring cause its default gateway (L3 switch or inside interface of ASA) is always available regardless which ASA is acitve or standby.

When ASAs do switchover the secondary one starts using the IP address of the previous primary one (which is default gateway for internal networks and L3 interface of PAN).

OK I've found the info that traffic handling links on the passive device are in "down" state. Of course it wouldn't make sanse the other way but I had to ask Smiley Wink

As I said I can't test it in a full environment but I have to do it in production Smiley Wink GREAT is it not?

What about your case you've mentioned earlier? is it closed with the solution presented? or still have hope for some trick? idea?



- Anyways we are getting rid of ASA with PAN so I am not bothered any more Smiley Wink. I wanted to simulate it for other environment.

Passive PAN in vwire mode will have all its interfaces shut/down. Are you seeing the interfaces UP? Also the traffic will eventually flow from the vwire to reach ASA or gateway so the path monitor will have no data on the passive PAN. Check the output below from passive PAN. There is a possibility that the active PAN will be able to reach the destination ip from the standby ASA (when Active). I did not get time to check about it. I will check with our SE.

pan(passive)> show high-availability path-monitoring


path monitoring statistics unavailable due to inactive device state

total paths monitored :                         1

interval to send ICMP probe packets :           200 ms

last N probes to determine path availability :  10

hold time to send probe packets :               60000 ms

  (after device becomes active)


name/type                        destination     succ/total rtt min/max/avg (ms)


ha-monitor-vrouter/virtual-router <dst monitored ip>       N/A         N/A


I tested it in production as well as I have running setup with this limitation :smileygrin:. I am going to try next with Juniper firewall which has the option to assign separate management ip address apart from the floating one to an interface.

As per support, it is not possible to monitor destination which is one hop away/routed. The L3 interface on PAN will have to be in the same subnet as dst address.

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