VPN not establishing because remote subnet the same.

[sindbad]

I have a FortiGate firewall and its acting as a HQ. I have couple of branches and the connection is great through VPN. Now I want to add a new branch. But the remote subnet is overlapping, that is why it’s not connecting. I already have a branch with that subnet. For example 192.168.0.0. When I change the remote subnet to 192.168.13.0, i do get a VPN connection. I can’t change the IP subnet of that branch. Is it possible to change it in the firewall of the FG? Thanks

[tanr]

The documentation has some examples of this: http://help.fortinet.com/fos50hlp/56/Content/FortiOS/fortigate-ipsecvpn/Gtwy_Gtwy_Config/How_to_Work....

There are also cookbook articles for 5.2 and 6.0:

https://cookbook.fortinet.com/vpn-overlapping-subnets/ 

https://cookbook.fortinet.com/site-to-site-ipsec-vpn-with-overlapping-subnets-60/

[sindbad]

Thanks for the documentation. I will do my best and configure it. If you or others are happy to assist me with it. I would greatly appreciate it. (I do have support on my fortigate). I do like the forum interaction and the people are skilled.

[Ashik_Sheik]

Hi,

Kindly update the case after we resolved the IPSEC between FGT and Sophos with overlapped subnets .

Regds,

Ashik

[sindbad]

@Ashik helped me with this case. All up and running. More information: ask me or Ashik. 

case closed.