how to configure gre over ipsec?

[Felixcao]

Anybody know how to configure gre over ipsec ?

from the 9.0,pa support gre tunnel and only one word describe about this feature.

• (Optional) Select Add GRE Encapsulation to enable GRE over IPSec.
  Add GRE encapsulation in cases where the remote endpoint requires traffic to be encapsulated within a GRE tunnel before IPSec encrypts the traffic. For example, some implementations require multicast traffic to be encapsulated before IPSec encrypts it. Add GRE Encapsulation when the GRE packet encapsulated in IPSec has the same source IP address and destination IP address as the encapsulating IPSec tunnel.

  Has anyone done any specific this configuration?

  Can you give me a description of the configuration? Thank you

[PavelK]

Thank you for posting question @Felixcao

My interpretation of what is written in documentation is: by selecting check box: "Add GRE Encapsulation" Firewall will add GRE Header (IP Protocol 47) between ESP and traffic going to the tunnel interface. For example TCP Traffic routed to the Tunnel interface where you configured IPsec will get first encapsulated into GRE, then into ESP. This configuration is there in place for example if you have on the other side regular Cisco router running running Tunnel interface in: " tunnel mode gre" with attached: "tunnel protection ipsec profile".

Kind Regards

Pavel

[m.dmitriev]

Should the GRE interface be on the PA side or will it be sufficient on the other side, for example on the Mikrotik or Cisco side?

Has anyone configured GRE over IPSEC between PA and Mikrotik? Please share an example of a working configuration.

[PavelK]

Thank you for the message @m.dmitriev 

The GRE encapsulation should be enabled on both sides. Without both sides having GRE in place, the traffic that gets encapsulated by GRE on one side would not be able to get decapsulated on the other side of the tunnel. Regarding your second question, unfortunately, I do not have any hands on experience with Mikrotik.

Kind Regards

Pavel