2011UiAS-2HnD 6.42.6 + integrated lan: Realtek RTL8168C/8111C PCI-E Gigabit Ethernet Adapter (PHY: Realtek RTL8211/8212)
nas has MTU 4074, router ports (MTU and L2 MTU) 4074 too.
without jumbo frames there is no problems at all
if 4k packets activated at client PC (win7 x64), after 1 gb transfer from nas (linux, debian x64) packet transfer freezes - packets go to router, and no packets returns from it.
there is nothing in log at router and pc.
4k packets can be disabled or no, lan connection can be disabled and activated, PC can be rebooted, with or without power disconnection - notthing happens - port is not returns packets.
de-activation and re-activation mikrotik port via new wifi card has no effect.
if port at router for PC will be changed, connection will restored, but for ~1 gb transfer…
port from NAS has no such problem, may be linux or FW has no problems
it’s not a problem with bad working realtek LAN at my PC, main trouble - is disabled port at router.
can add any logs of configs.