We have a network with 40 users. Up to 30 might use the network at the same time.
About a month ago we changed our ISP provider. Since then we have been experiencing intermittent communication errors to all 3 servers. There are about 15 error messages a day. Most of them are to the SQL server, but we also have a few to the LAN server and to the Exchange server.
We think the communication failures are not related to the ISP provider change, since the change had not included hardware or software updates. However, we might be missing something about that.
Since many of the error messages mention Microsoft ODBC SQL server Driver, we removed some old unused FoxPro ODBC drivers on workstations that were used to generate Crystal reports using FoxPro files. It seems that removing the FoxPro ODBCs from work stations might be helping the situation temporarily. That also might be a coincident. We have been using the same ODBCs for about 10 years without any problems for generating Crystal reports from our Visual FoxPro accounting system without causing any problems. It is hard to judge what helps since the issues are intermittent.
Some potential clues: Many times the communication errors take place when the work station had been inactive for a while.
Some times during heavy usage the whole system slows down and several people get communication failures around the same time.
Some times after experiencing a loss of communication to the SQL server, we notice that the workstation shows a message Connection to the Microsoft Exchange Server has been restored.
Most of the error messages are the following:
Error # [ 1526]: Connectivity error: [Microsoft][ODBC SQL Server Driver] Communication link failure SQL command &.
Error # [ 1526]: Connectivity error: [Microsoft][ODBC SQL Server Driver] [DENTLIB]ConnectionWrite (send()). SQL command &&
The SQL command that fails varies, but these are all commands that have been working properly for years.
Error reading file &
The file being read varies, but these are all major files that all other users are able to read. These are errors related to files on our LAN server.
We have a Windows LAN server with Windows Server 2003, a SQL 2005 server (on another machine with Windows Server 2007 copyright) and an Exchange server.