forging headers

So I got this message. How would someone identify the sender of this message? I'm writing an article on anonymity, with some discussion of remailers, and want to argue that forging already permits people to raise the costs of tracing significantly, anonymous remailers or no. Lee

From: freeh@fbi.gov Date: Tue, 24 Oct 95 16:07:08 -0400 Apparently-To: tien@well.sf.ca.us X-UIDL: 814570964.056

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How difficult is it to forge headers? How difficult is it to trace a message to the actual sender if the header is forged?

Not very difficult at all (to forge, that is). This is a quick and dirty example that should be somewhat traceable. If you want pointers on how to trace it, post the whole thing, including headers, to cypherpunks.

Louis