How do I add an I.P. Address through codebehind to the "IP Address and Domain Restrictions" table in IIS

I can manually add an I.P. address to the IP Address and Domain Restrictions form in IIS, but how do I do that in codebehind dynamically. 
In my web App, after a user has provided their login information, I want to be able to add their I.P. address to the list so that they can access the site automaticaly through codebehind.
 
Thanks
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