Re: IPSec Dual Stack cant handle IPv4 and IPv6 at the same time
to your questions.
Did you run "diag vpn tunnel list"
-> Jup, the tunnel is shown stable and nothing unusal
did you run debug on fortigate for ike
-> Jup, the tunnel is established and no error signs
Did you run ipsec statusall & looked at the logs on Strongswan host
-> Jup, also i had done this, but strongswan gets no response from the fortigate and the ip (seen with "journalctl -f" on linux); the fortigate logs shows nothing
Did you try with specific Phase2 in both fgt and strongswan
-> I tried, for example to set in particular "compress=no", but nothing works. In the end I only use the default configuration of strongswan
For me it looks like that Fortigate dont support a dual-stack client-to-client roadwarrior vpn.