In ASP.NET 4.0 there are new features that enable developer to make SEO friendly websites very easily. And if you google out, you will find plenty of article which explain this feature. But I am more interested in Response.RedirectPermanent. As the name suggest it is used to redirect permanently moved resources to new location. And most of all articles on the net just explain this with some example. But how can we visualize that whether resource is redirected permanently or not. So here is the answer for that. I have used FireBug to examine the same.
Whenever we redirect with Response.Redirect, we can see following activity in FireBug console.
As we can see that page which issues Response.Redirect its response status code 302(Found) which means requested url(default.aspx) is found but it is temporarily moved to about.aspx. More information on HTTP status code can be found here.
Now whenever we redirect with Response.RedirectPermanent, we can see following activity in FireBug console.
As we can see that page which issues Response.RedirectPermanent its response status code 301(Moved Permanently) which means requested url(default.aspx) is moved Permanently to about.aspx. 301 status code is used by search engine crawler to update search index to new moved information.
I hope information provided here would be more helpful to distinguish between Response.Redirect and Response.RedirectPermanent.