Apart from different environments, sometimes, there are others changes. Sometimes the client may change the drive from C to D or D to E, or change the Database name. If you are using SMTP mail servers, you may have to change the server IP and authentication when the environment changes. So whenever the environment changes, you may have to change all the configuration settings associated with SSIS packages.
You can avoid all the headache of changing these settings by using package configuration.
Here are the steps to setup Package Configuration in SQL Server 2008.
1. Once the SSIS package is developed, Right Click on surface area and select Package Configurations...
5. Suppose we need to select database settings for OLEDB Connection Manager Local.MyDatabase which is the connection manager for the SQL Server database. Then you will need to select the properties you require to save as a package configuration from the following screen.
For connection manager, you can either select entire ConnectionString property or you can select ServerName, UserName, Password, and InitialCatalog to construct the connection string. I prefer latter one as it gives more options when there is a change.
6. Click on Next button followed by Finish button to complete the wizard. Now you can see config.DtsConfig file at the location you mentioned in step 3. Below is snapshot of config file (I did some formatting for better visulation)
I personally prefer using Package Variables in config file instead of connection managers because that gives me facility to use in hundreds of packages where Server and Database name are same. however, you need to map the variables in connection manager properties.