I used the below code to Set IP Security from my vb.net Application. It is working in IIS 6 (windows xp, and server 2003).
facing error in IIS 7.5 (windows7).
' Get the IIS object that holds the info for the default site.
Object = GetObject("IIS://LocalHost/W3SVC/1/Root/WebServerSCM")
' Get the IIsIPSecurity object.