Solar, that is premature as we do not know what kind of WAN scenario the OP is envisioning?
If I told you it was 1 Main WAn with 5 for failover (unlikely) OR
1 Main WAn and 5 for direct public IPs to servers (could be) OR. etc.....
You are probably right but it bugs me to know end when people much smarter than myself on mikrotik stuff, start assuming requirements.
The one question I do have is that for every outbound connection intiated behind the router, isnt connection tracking noting where it came from (lanip) and where it went (outbound WANIP) and thus return traffic from the same WANIP will then get routed to the right internal (LANIP)??
No mangling required there........
The next question alludes to lets say, INPUT FROM ANY of the 5 wans are coming in and they all point to SERVER (Im assuming that is what is meant by a node). In this case we are talking inbound unsolicited traffic and as such has a destination port (and maybe a source address list associated). IF the dst-nat router rule is such that
any inbound traffic in-interface-list=WAN, is routed to a specific server on a specific LAN, that traffic IS CONNECTION TRACKED by the router and thus the router know which WAN it came in on and where it went. Why is not safe to assume that server return traffic would then be sent to the correct WANIP by connection tracking?????????
In other words, I still see no need for mangling.
I feel I am missing something but what????