Network Protocol for SQL Server Connection

To explicitly define which network protocol to use when connecting to an SQL Server gives you more control over your connection. This guide explains how to do that.
Written by: Sebastian Affakes

Specifying the network protocol isn't hard at all. Knowing about the underlying communication can improve performance and helps to avoid connection issues. Especially in a dev-prod issue situation. Shared Memory connections are great when it comes to performance but can be used only if the application and the database instance is located on the same machine. TCP/IP is often the best for a firewalled environment.

This connection string exemplifies how the network specification can look like inside the connection string.

Provider=sqloledb;Data Source=,1433;Network Library=DBMSSOCN;Initial Catalog=pubs;User ID=myUsername;Password=myPassword;

Network protocol codes

Name Network library
dbnmpntw Named Pipes
dbmslpcn Shared Memory (local machine connections only, might fail when moving to production...)
dbmssocn Winsock TCP/IP
dbmsspxn SPX/IPX
dbmsvinn Banyan Vines
dbmsrpcn Multi-Protocol (Windows RPC)
dbmsadsn Apple Talk
dbmsgnet VIA

Important note

When connecting through the SQLOLEDB provider use the syntax "Network Library=dbmssocn" and when connecting through the MSDASQL provider use the syntax "Network=dbmssocn".


Using the most appropriate network protocol will improve your application and gives you, as a developer, insight in the underlying connection mechanism. It's definetely a developer-operations peace maker.