Fail-over VPN site-to-site

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L4 Transporter

Fail-over VPN site-to-site

Hi,

 

We have a PA with two VPNs configured. VPN-Main is the active one and if this vpn falls, the traffic must go through the other VPN-backup. The fact is that when the active VPN falls, the route that has the Palo Alto continues going through the previous VPN, it does not refresh the route and adds it through the new tunnel.

This configuration worked when this deployment was done but suddenly stop working.

 

We have configured a tunnel monitor with destination IP and profile fail-over.

 

In VPN Main (active):

 

1.JPG

 

In VPN (backup):

 

2.JPG

 

And this is the route table:

 

3.JPG

 

tunnel.29 is the main (active). The metric is 2.

tunnel.27 is the backup. Metric is 5.

 

Why PA is not deleting the "active" route if the monitor ip is down through the vpn down.

 

 

L7 Applicator

Re: Fail-over VPN site-to-site

Hello,

Its because they are static routes. For this type of config I would recommend one of the following.

 

For VPN tunnel A

Use Policy based forwarding with the monitoring and "Disable this rule if nexthop/monitor ip is unreachable" checked.

Then use a static route for tunnel B

 

The PAN will enforce PBF policies prior to the routing table so when the PBF disables its self the routing table takes affect.

 

The second option is to use PBF for both tunnels and tunnel B lower on the list. The firewall reads these from top down so it will always prefer tunnel A unless it goes down then switch to tunnel B.

 

Hope that makes sense.

L4 Transporter

Re: Fail-over VPN site-to-site

Yes, but its not necesary PBF. It should be work only with tunnel monitoring

 

https://docs.paloaltonetworks.com/pan-os/7-1/pan-os-admin/vpns/set-up-tunnel-monitoring

 

Whats the problem with static routes???  static route should dissapear when monitor ip is down.

L5 Sessionator

Re: Fail-over VPN site-to-site

Hi @jesuscano

 

The static route will be removed from the FIB not the RIB - if you go to the VR and click "More runtime stats" -> "Forwarding Table" it shouldn't be there.

L4 Transporter

Re: Fail-over VPN site-to-site

but the new traffic should use backup tunel, since the static route dissapear for active path.

 

L7 Applicator

Re: Fail-over VPN site-to-site

Hello,

In the static route, was the Route monitoring configured? Sorry if I missed it somewhere in the thread?

 

https://docs.paloaltonetworks.com/pan-os/8-0/pan-os-new-features/networking-features/static-route-re...

 

Regards,

L5 Sessionator

Re: Fail-over VPN site-to-site

Hey @Otakar.Klier

 

I may be completely wrong here, but the way that I thought it worked was that if you had tunnel monitoring configured with action of 'fail-over' the actual failover mechanism works by removing any static routes associated with that tunnel interface from the FIB - effectively making it so you can start using another IPSec tunnel via routes in your RIB.

 

https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-admin/vpns/set-up-site-to-site-vpn/set-up-tunnel...

 

Reading the documentation - when failover option is selected, tunnel interface is disabled so all routes with that tunnel interface are indeed removed from the FIB. So yes @jesuscano this setup is valid and the traffic would start using the backup tunnel so long as your primary tunnel has tunnel monitoring with failover option set.

 

Cheers,

Luke.

L4 Transporter

Re: Fail-over VPN site-to-site

PanOS is 7.1.x. It this version there is no path monitoring in the static route.

L4 Transporter

Re: Fail-over VPN site-to-site

So the version is 7.1.x. We think that its all configured properly but we dont know why its not working

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L7 Applicator

Re: Fail-over VPN site-to-site

A ticket with support may help find the rason why.

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