IPsec tunnel takes long time to re-establish

[CTramier]

Hello,

We have 2 IPsec tunnels s2s between 2 Palo Alto firewalls.

We are using ike-v2 gateways, and liveness check : 5s

The WAN on one of the side is flapping, sometimes disconnect around 10min. After this disconnection, the tunnel does not re-establish immediately, it takes around 15min.

We have also configured tunnel monitors on both sides, we have assigned IP addresses on tunnel interfaces, and we are monitoring these IPs, the monitor are UP and active.

Do you know why it's not reconnecting immediately after the WAN back up ? Is there something to do in terms of config ?

[CTramier]

In fact, when the public IP is reachable again, we can see the tunnel is briefly re-established then go down again, and we need to bounce it manually to have it reconnected.

[ksalustro]

I am seeing a similar issue that I'm trying to work through. In your setup, is there is a single WAN interface at the site, or are you failing over to another WAN interface? Is either side of the tunnel in dynamic, or passive mode?

Do you have "Liveness Check" enabled in the IKE settings?

[ksalustro]

Also is there any NAT involved and if so, do you have NAT-T enabled?

[nikoolayy1]

Better enable IKE debugs and to see what is happening as to not make wild suggestions:

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClivCAC

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClcKCAS

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000PORsCAO