Dear all, here is the schema :
modem bridge ==> Mikrotik RB2011 UAS-RM (v6.38.1) client <==> Fortigate
There is a gre tunnel between mikrotik and fortigate. All the trafic is routed to the Fortigate But i have a problem, some websites (HTTPS essentialy) won’t open.I have the problem only through GRE, if i try through Eoip tunnel,(with a mikrotik between Mikrotik and Fortigate) all is working fine.
I think that i have a problem with MRU, MTU or TCP MSS. I have tried to modify the MSS regarding this : /ip firewall mangle add out-interface=gre-tunnel2 protocol=tcp tcp-flags=syn tcp-mss=!0-1436 action=change-mss new-mss=1436 chain=postrouting but it is not working.
What is wrong?
Thank you in advance,
Regards,