Unfortunately it appears that Patrik Koetter's website is now defunct
and the domain has been taken over by someone else completely leaving a
number of resources linked to from postfix.org broken including (but
probably not limited to):
The saslfinger utility linked to from DEBUG_README.
The Postfix SASL Authentication and TLS howto linked to in two different
places on the docs page.
Fortunately There are copies of the above listed resources on
Archive.org's wayback machine: