[metafunctor]

How does it work?

Based on a cursory inspection, it looks like UniversalSPF makes use of a custom DNS server and the the %{i} and %{o} macros for SPF.

Before this, I wasn't even aware that SPF had macros!

[hoseja]

Quick, somebody prove it's Turing-complete!

[kcolemangt]

It works by inactivating spf terms that cause errors then serving out a cleaned up and compressed policy for you on the fly.