Forticlient 6.4.1 - MacOS 10.13 - Traffic not going through SSL Tunnel

[ymagis_bo]

Hello

We configured SSL Tunnel on our main firewall and are using Forticlient (free version) in order to connect to our main infrastructure. RFC1918 routes are pushed through the tunnel and DNS is updated to use internal DNS

--> Once connected with forticlient, DNS requests will go through the tunnel, traffic to internal IPs will go throught the tunnel but public traffic will remain on main NIC using normal internet access

Windows version is working fine. Mac is version has a really strange behaviour.

From time to time (even if lately always), we got following behaviour. This happens in all our MacOS of the company :( :

- None of our cloud applications (Teams, Slack, VoIP...) is working, probably due to DNS resolution issue

- Browser is not working. Public webpage, internal webpage and internal webpage accessed through IP address.

- Nevertheless, when opening a terminal, I can resolve DNS, ssh our servers, telnet internal webpages on port 443. Everything is working fine.

I sniffed traffic on Mac and on fiirewall and I can see request going through the tunnel but it looks like applications don't interpret the answer :(

Any idea where it could come from ?