I have SG300-24 in L2-Mode uplinked to Sonic FW. The only settings that seemed to work is
100Mb Full-duplex on both sides. If there is any other setting like auto-auto or 1000Mbits on both sides link goes down.
I also set portfast enable on the cisco port. Is there anything I need to check to make 1000Mbits work?
PS: L3 mode did not work for us.