Hi guys,
I use two VPN connections to remote sites: PPTP client on RouterOS directly, and OpenVPN tun client routed via external box (as Mikrotik does not support it...).
I use both RB2011 and RB3011 - and on both routers local traffic works perfectly fine, but whenever I activate fasttrack connection for local LAN, for established and related in forward chain (on RB3011 I tested with default config) - TCP packets to be sent through VPN tunnels die after sending 3965 bytes, no more, not less, always after sending 3965 bytes... So ping, and other diagnostic services work fine, just not larger data packs... And that happens only when fasttrack connection is active in firewall filters - disabling fasttrack solves the problem, just then creates issue with performance. I double checked MTU, it is set everywhere to 1500. I also tested this with 6.37rc34 and the problem is still there...
Any idea what could be wrong? For me it sounds like RouterOS bug, but I'm not really expert...