C# HTTP Headers crafting

Since Http Headers can be crafted and customize, how would I change or modify the IP part of it 开发者_C百科using C# 's HttpWebRequest class. In other words, how can IP Spoofing be done using C#.

Thanks for reading.

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Sorry can I ask why you need that ? Looks for hacking purposes. Anyway if it is not for hacking may be we can find another solution without replacing IP.