WAN to WAN Connection
We share the same public subnet with 2 other entities. All 3 entities use the same gateway.
For example (please assume that the IPs belong to a public block):
C: Has the rest of the subnet IPs except the ISP IP
I created a VIP and a firewall policy and made sure that those are working (did tests from home, made a successful connection). My issue is: I cannot make the same connection when I try to connect from any other entities' private subnets (Let's say, the packet originates from entity B's WAN IP (10.1.1.12) and arrives to my firewall's WAN 10.1.1.11). On my firewall (FortiGate 100F, v7.0.1) I see that the packet arrives but it is not directed anywhere (simply dropped, checked it using cli "diagnose sniffer packet any..."). I tried to add a WAN to WAN any any accept rule for test and that did not work either. The other interesting thing is, I did not see a log for this blocking activity. Though I should say that I might have configured the logging settings wrong.
I am currently replacing our old Palo Alto firewall with the FortiGate. I had the same rules/NATs on that Palo Alto firewall and I never had any issues (I am just trying to say that there is no other entity firewall rule that is blocking this kind of connection).
Can you please help me with this problem of mine? I believe I am missing something simple. Thank you in advance.