[EXIM] fetchmail + rbl?

I'm currently using exim-2.10 with fetchmail-4.5.8. I'd like to use
the rbl on exim, but will it work? Do I need to configure fetchmail
any particular way? (As far as exim knows, all mail is coming from
127.0.01. Will it check the source address against rbl? Or will it
check the From: header?)

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