GRE tunnel via existing IPSEC tunnel

[AlexR1]

Hello,

We have an existing VPN site to site in hub n spoke with IPSEC.

In remote sites (spokes) , we have Aruba Access points that have to mount a GRE tunnel to an Aruba Wireless Controller in central site (hub).

I would like to know if it is possible, because Wireless controller send data to Access Point but access point is not responding.

Have i to change MTU for this IPSEC tunnel?

FortiOS 6.2

Thanks for help.

Regards.

[Toshi_Esumi]

If Aruba controller and APs are the ones that encapsulate IP packets in GRE, they are the ones to adjust MTU (-8) before the encapsulation. Not FortiGates.

But if much shorter packets, like small ping packets, don't go through, the MTU is not the problem.

Toshi

[AlexR1]

Yes, it is controller which encapsulate. ping are OK between AP and Controller.

I will try to ajust MTU.