ChittaranjanMuduli
Are you referring to the Old SiteMinder Applet Based UI? OR the new WAM UI? I am assuming you are referring to the old one. Please confirm this and the Version of SiteMinder.
Also are you referring to Web Domain of GUI or Cookie Domain or Policy Domain - please could you clarify.
If Web Domain of UI, Then.....
It is fairly easy to do it via WAM UI by protecting the WAM UI using an SPS or WebAgent WebServer.
Protecting the Administrative UI - CA SiteMinder® - 12.52 SP1 - CA Technologies Documentation
Regards
Hubert