under appsettings in your web.config add one more key Eg:
<add key="my_ip_address" value="192.168.10.1"/>
and in you code you can use this key as follows
string ip_path = System.Configuration.ConfigurationManager.AppSettings ["my_ip_address"].ToString();
This way you can get you ip address in a string, customize this as per your requirement, this is just an example.
I hope this will help you out.