Ghost session after VPN down/up

[Mamoudou]

Hello,

I have an issue with many sites working with PA440 series. When the tunnel VPN fail down and comes up, some devices like printers, phones and access point can't connect normally to the network until that we clear old session related to the affected device.

In printer we have job blocked and offline, access point also offline.

Once we cleared the session the devices work correctly.

This issue happen after every change of the VPN tunnel status(down/up)

Could anyone help me to understand this weird behavior ?

Thanks in advance.

[PavelK]

Hello @Mamoudou

we were experiencing this issue in many sites connected by ipsec tunnel.

What I have noticed is in normal condition, traffic from branch site goes from trust zone to vpn zone, however when tunnel goes temporarily down the sessions are traversing from trust zone to untrust zone. When tunnel is back online, the sessions are still traversing from trust zone to untrust zone until they get cleared from session browser. In particular, we had this issue with UDP sessions (DHCP, RADIUS, CAPWAP).

Eventually, we came up with the script that runs regularly to connect to each Firewall running ipsec tunnel to clear UDP sessions we were having an issue with. Based on what you described, it sounds like you are hitting the same issue. Unfortunately, it is hard to advice what to do other than automating clearing of the sessions.

Kind Regards

Pavel

[ozheng]

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA14u000000HBmqCAG

Hope that helps.

Olivier