Dropped Database Connections in SQL Server 2008R2 We are having an annoying intermittent problem where database connections from our client application on a variety of stations will get dropped.  We have applications that use ODBC, Borland Database Engine, and ADO and all get dropped.  When connections do get dropped, it isn't everyone - some remain connected while others get dropped.  Looking in the logs of one of the applications, I see messages like the following:


TCP Provider: The semaphore timeout period has expired
TCP Provider: An existing connection was forcibly closed by the remote host
Query timeout expired
TCP Provider: No such host is known


I don't see any error messages in the SQL error log or in the Windows events on either the client or the SQL Server.  Is there anyway to determine if this is a database or network issue from the SQL Server side of things?  For example, is there something I can turn on to monitor database connections and get reports when they are dropped?  This happens maybe once or twice a day but not at any specific time (not when backups run or something).



The issue seems to be network related and out of scope for this forum.
It can be SQL related, not just OS and hardware:

https://support.microsoft.com/en-us/kb/2491214