Fortigate Site-to-Site VPN Cannot view VDOM Local Network

[TabrizKhaligov]

* Fortigate VDOM is configured. s2s vpn is established over MPLS channel with Location B on ExFW.

* InFW users and Location B users access the Internet through ExFW, NAT goes there.

* Location B users should see the Server network on InFW.

* The InFW Server network sees the Location B user network.

[Debbie_FTNT]

Hey TabrizKhaligov,

this may be a stupid question - but is there a firewall (like Windows Firewall) on the InFW server that might block ping? I would suggest a traceroute from the location B PC to InFW server, to figure out which hop is the issue.

If ping works in one direction, but fails in the other that usually indicates that either the ping destination is set up not to respond, or a simple policy/permission is missing somewhere to allow traffic in the other direction

-> FortiGate would handle reply traffic on the same policy the original traffic matched to, but traffic originating in the other direction would need a separate policy

-> that is frequently a reason for ping to work in one direction but fail in the other

[Toshi_Esumi]

If the policy for the direction toward the server is ok in both two VDOMs, you need to sniff the packets at VDOM1 first then in is passing them to the vdom-link/npu-vlink, sniff at VDOM2, to figure out where the dropping point is. And then run "flow debug" to find out why it's dropping.

By the way, not sure why you need to have a p2p vpn over MPLS. MPLS is basically VPN.

Toshi