Recently we have bought few SG300's for our office (120 users). Time to time some of users are complaining about connectivity issues - they are lossing IP's, but port lets are blinking on both, network card and switch port. When I check in GUI, it shows 10 mbps for such ports, however, there is not connectivity and it's supposed to run on 1Gbps. Any ideas where to look? One again, not all of the ports have such issues, only few and this isn't permanent.
One thing that may be causing this is the Green Ethernet feature. Under Port Management>Green Ethernet and turn it off. If that is not the issue then you may be getting IP conflicts some where on your network.