[solved] strange routing Problem on two 300E

[sw2090]

Hi Folks,

I have the following constellation:

two FGT 300E are directly connected to each eather via Port 28. 

FGT A Port 28 has 10.0.1.1/24 and FGT Port 28 has 10.0.1.2/24.

On both FGT Port 28 has ping enabled.

Now if I ping from A to B and have flow debug running I can see that packets from FGT A arrive on FGT B via Port 28 but the reply gets dropped an FGT B because of RPF (Remote Path Check Failed. Drop.). 

Routing Monitor (and CLI) show that there devinitely is a route to 10.0.1.0/24 via Port 28 on bot FGT. So I assume there IS a definied reverse path. This is common use if you have an Interface in a network.

So I assume the Error is not the real error that occured.

Same happens btw in the other direction.

As an additional info I'd like to add that currently FGT B does not have any policies as I want to add it to my FMG and then roll out the default policy package of the specific adom. Maybe the problem is somewhere here? However a policy from an interface to itself and from a subnet to itself makes no sense at all....

Does anyone have any advice here?

[sw2090]

In fact the problem was that on FGT B the Interface hat Subnetmask /32 (255.255.255.255). I set that because I had cases where the FGT did not accept a single IP with /24 as Subnetmask. After I changed that to /24 (255.255.255.0) it started working as it should.