After I use synonyms for my base domain - how do i get correct URL?

For instance...

base domain: site.p synonym: site.com

I open "site.com" and that i see during my browser "site.com".

But!

HttpContext.Current.Request.Url.AbsolutePath
HttpContext.Current.Request.Url.Authority
HttpContext.Current.Request.Url.DnsSafeHost
HttpContext.Current.Request.Url.Host
HttpContext.Current.Request.Url.OriginalString

Each one is "site.p"