additional details for fortinet VPN site-to-site configuration

[Alejandrodelgado]

as documented in cs3689825
and documented here
https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-FortiGate-sends-local-id-in-FQDN-type-when/ta-p/224888
and here
https://docs.strongswan.org/docs/5.9/support/faq.html

In case of different internal and external IP in Fortinet this is the solution to avoid "no matching peer config found" error
Dont leave localid-type in auto, in case localid can not be set after change localid-type set to address , open a ticket in Fortinet.

config vpn ipsec phase1-interface

 edit 1
   set localid-type address
   set localid <external-ip>

end