Network

I am having issue where the connection to our server keeps dropping whether local or through our VPN connection. We are running Sonic Walls for the VPN. Specifically of note, we are accessing Access Databases and the connection drops randomly. How can I best determine where the problem is at and work at fixing the problem. Coupled with that I found a strange IP Address that was part of the Network Monitor log. How can I determine what is hitting that address and why? Thanks.