Restrict access to VPN Tunnel Terminator
I have a VPN tunnel to Azure. In the logs, I see random sites attempting Phase I with the VPN Tunnel interface on the Fortigate. They fail of course, as they aren't sourced from the specified IP address nor do they have the pre-shared key. But I don't enjoy seeing these messages in the logs.
How might I go about applying a Policy to prevent these packets from even reaching the IPSec VPN Tunnel interface? As I poke around, I'm realizing that I don't even know how FortiOS handles this -- I don't see any IPv4 Policy which permits IKE / ESP to my tunnel interface. I do see Local In Policies which seem to permit UDP 500 / 4500 / 1701 to *any* interface. And IPv4 Access Control List doesn't seem to be granular enough -- only supports Denies -- no Allows.
Is Local In Policy the place to start, in terms of attempting to lock this down?
--sk