"Load Balancing" as we all here in the forums strive to achieve, without success, is with NATing - yes.
hmmm... without? we used load balancing between 3 modem lines successfully 2-3 years ago =) fortunately, now we are ISP and use one uplink line
and "Load Balancing" is not NAT, it is selecting one of uplink/downlink lines. actually, NAT in our scenarios is just a means to use the same link for download traffic =) so, at first you should decide how you will separate requests between lines
Russian-speaking forum: https://forum.mikrotik.by/
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