@moneron открой секрет ровного SSTP.

/interface pppoe-client
add add-default-route=yes allow=chap,mschap1,mschap2 disabled=no interface=ether1 name=INTERNET-ADSL password=password  user=userpppoe

/interface sstp-client
add authentication=mschap2 connect-to=s100401.pointtoserver.com disabled=no keepalive-timeout=30 max-mtu=1000 name=PureVPN-SSTP password=password profile=default-encryption user=purevpnuser

/ppp profile
add change-tcp-mss=no name=pppoe-without-change-mss use-compression=no use-encryption=no use-mpls=no use-upnp=no
add change-tcp-mss=no name=sstp-without-change-mss use-compression=no use-encryption=no use-mpls=no use-upnp=no

/ip firewall mangle
add action=mark-routing chain=prerouting new-routing-mark=PureVPN-SSTP passthrough=yes src-address=172.12.0.250-172.12.0.254
add action=change-ttl chain=prerouting new-ttl=increment:1 passthrough=yes
add action=change-mss chain=forward in-interface=INTERNET-ADSL new-mss=1452 passthrough=no protocol=tcp tcp-flags=syn tcp-mss=1453-65535
add action=change-mss chain=forward new-mss=1452 out-interface=INTERNET-ADSL passthrough=no protocol=tcp tcp-flags=syn tcp-mss=1453-65535
add action=change-mss chain=forward new-mss=1300 out-interface=PureVPN-SSTP passthrough=yes protocol=tcp tcp-flags=syn tcp-mss=1301-65535
add action=change-mss chain=forward in-interface=PureVPN-SSTP new-mss=1300 passthrough=yes protocol=tcp tcp-flags=syn tcp-mss=1301-65535