IPSec VPN not working before phase 2 negotiation

[yhlee1]

Hello,

I made an VPN Tunnel between paloalto and fortigate(3 tunnels).

Every config is same between them. 2 of them work well but 1 tunnel has an issue.

About 3 mins before phase 2 negotiation(by lifetime or other reason), traffics can't go through the tunnel.

(I can see traffic logs that incomplete).

After negotiation and install sa, it works normally.

What should I look? There no error log or fail in ikemgr or system log.

[Raido_Rattameister]

Check renegotiation time. Does it match with peer site?

[yhlee1]

Yes
I checked again and it’s same both ends

[Raido_Rattameister]

When traffic does not pass any more from one side to other then try to initiate traffic from other side back to your side. Does traffic flow then?

[yhlee1]

I think it will work
After phase 2 negotiation ends, it works
It worked when I disable/enabled tunnel.
Issue happens occasionally, 2 or 3 times a day, so I need to remove the cause..

[Raido_Rattameister]

I would check tunnel status at other side when it happens.

[yhlee1]

Thanks,

I want to check it but I don't manage that device...  So it's hard to check other side.

[SShnap]

Hi @yhlee1

I have the same issue with old and stable ipsec tunnel between PA3020 (8.1.1) and VM200 (8.0.10).

suddenly the tunnel is not working even when the connection looks fine and system logs show tunnel is up.

on source side I see traffic go to tunnel and aged-out, on destination side logs don't show the traffic.

when I change something on the tunnel config and revert the changes or disable/enable the tunnel it come back to normal.