Question:
While logging in Siebel dedicated client, data source options shows ‘local’ by default, how can you change it?
Strange question isn’t it. I know when I read that question I thought what a simple question. But when I asked this question to some people they were unable to tell the answer then I realized that you need have through knowledge of Configuration (CFG) file to answer this question.
I believe my mention of CFG file might have give pointers to some people about the answer and they might already know the answer 
. But still the number of those people would be pretty less.
Answer:
You need to go to your respective client or tools CFG file which can be Siebel.cfg, uagent.cfg or something else depending on the application or object manager that you are using. In this example we will take uagent.cfg file
Go to section labeled as [Siebel] in the CFG file
Search for DataSource in that section. You should see local written against that
DataSource = Local
Change that to the name of the datasource that you want by default. To have server as default value you should change that value to
DataSource = Server.
and you are done.
To know more about CFG file details you can read This entry.
