I configured stie to site VPN between 2 Fortigate firewalls and the tunnel is down
I have 2 Fortigate sites
Site 1 : FGT60 use DDNS
i have 3 WAN interfaces (Wan 1 , Wan 2 , Wan 3) connected to internet through ADSL router so they have private IP and router do NAT for real IPs these interfaces are connected to SDWAN zone with IP (0.0.0.0/0.0.0.0)
If your site-to-site VPN tunnel is down, there are several things you can check to troubleshoot the issue:
1. Verify the VPN configuration: Make sure that the VPN configuration settings on both FortiGate devices are correct and match each other. Check the remote gateway IP address or FQDN, the local gateway IP address, and the authentication settings.
2. Check the WAN interfaces: Make sure that the WAN interfaces on both FortiGate devices are up and running. Check the physical connections, and check the interface settings to make sure they are configured correctly.
3. Check the firewall policies: Make sure that the firewall policies on both FortiGate devices are configured correctly to allow traffic to pass through the VPN tunnel. Check the source and destination addresses, the protocols and ports, and the action settings.
4. Check the SD-WAN configuration: If you're using SD-WAN to load-balance your WAN interfaces, make sure that the SD-WAN configuration is correct and not causing issues with the VPN tunnel. Check the routing settings, the link monitoring settings, and the interface settings.
5. Check the logs: Check the logs on both FortiGate devices to see if there are any error messages or warnings related to the VPN tunnel. Look for messages related to the VPN configuration, the WAN interfaces, and the firewall policies.
Regarding the DDNS issue, if one of the FortiGate devices is using DDNS and the DDNS service is down, this could cause the VPN tunnel to fail. You may need to switch to a static IP address or use a different DDNS service to ensure that the VPN tunnel stays up.
I hope this helps! Let me know if you have any further questions.
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