I don’t think this is related to number of connections (could still be wrong though)
I converted the router to not need TCP tracking and moved the NAT functionality elsewhere. Problem still exists, TCP connections are dying
It’s similar to some threads i’ve managed to come across, except adjust connection values on every router between customer and DC has still made absolutely no difference
http://forum.mikrotik.com/t/tcp-session-connection-tracking-bug/99283/1
http://forum.mikrotik.com/t/question-about-tcp-established-and-call-of-duty-disconnects/144346/1
I’m stumped, no idea what to do here. Have confirmed a 1500 byte packet can go in both directions successfully, doesn’t appear to be MTU related, despite that using 1400 byte L3MTU helps (a bit, not entirely). It does seem to be less drastic at nighttime when its quiet, during the day it was causing large downloads to fail in ~30s-15m but its night time right now and it can go for much longer before it fails. RDP sessions are still dying but downloads tend to go longer