Thanks for your response!!
Seems like I need to update my router config skills quite a bit...
Have tried to implement your suggestions. Does this seems better? (will not be able to test before doing the changes at customer's site next week...
-Olaf
/ip firewall filter
add action=accept chain=input comment=\
"defconf: accept established,related,untracked" connection-state=\
new,established,related,untracked log=yes
add action=accept chain=input comment="Accept Winbox" connection-state=\
new,established,related,untracked dst-port=8291 log=yes protocol=tcp
add action=accept chain=input comment="defconf: accept ICMP" protocol=icmp
add action=drop chain=input comment="defconf: drop invalid" connection-state=\
invalid
add action=drop chain=input comment="defconf: drop all not coming from LAN" \
in-interface-list=!LAN
add action=accept chain=forward comment="defconf: accept in ipsec policy" \
ipsec-policy=in,ipsec
add action=accept chain=forward comment="defconf: accept out ipsec policy" \
ipsec-policy=out,ipsec
add action=accept chain=forward comment=" Accept MSTSC" connection-state=\
established,related dst-port=3387 protocol=tcp
add action=accept chain=forward connection-state=established,related dst-port=\
3388 protocol=tcp
add action=accept chain=forward connection-state=established,related dst-port=\
3389 protocol=tcp
add action=drop chain=forward comment=\
"defconf: drop all from WAN not DSTNATed" connection-nat-state=!dstnat \
connection-state=new in-interface-list=WAN
add action=fasttrack-connection chain=forward comment="defconf: fasttrack" \
connection-state=established,related
add action=accept chain=forward comment=\
"defconf: accept established,related, untracked" connection-state=\
established,related,untracked
add action=drop chain=forward comment="defconf: drop invalid" \
connection-state=invalid
/ip firewall nat
add action=masquerade chain=srcnat comment="defconf: masquerade" \
ipsec-policy=out,none out-interface-list=WAN
add action=dst-nat chain=dstnat dst-port=3387 protocol=tcp to-addresses=\
192.168.1.129 to-ports=3389
add action=dst-nat chain=dstnat dst-port=3389 protocol=tcp to-addresses=\
192.168.1.128 to-ports=3389
add action=dst-nat chain=dstnat dst-port=3388 protocol=tcp to-addresses=\
192.168.1.32 to-ports=3389