How to find webconfig file on iis server

Using Visual Studio, You can find Web.config file in Your Application Treeview from Solution Explorer Window. Edit the underlined part to Your new IP addredd
 
<add name="XXXXX" connectionstring="Data Source=<u><b>10.1.1.1</b></u>; user id=XXXX;> <br mode=" hold=" /><br mode="></add>
 

Open the web.config file for the Web service that you want to modify.
 
The web.config file is found in the virtual folder for the Web service, such as C:\Inetpub\wwwroot\LoggingService.
 
Locate the <connectionStrings> element.
 
In the <add> element, set the connectionString attribute to the new connection string.
 
For example, to change the server name, in the connectionString attribute, change the value of the Data Source string