dnssec postfix use:

NOTE:  The current spf2 patch for postfix will only work with
       libspf2-1.0.x (i.e. it does not currently work with
       libspf2-1.2.x).  When installing dnsec-tools, use
       libspf2-1.0.4 and its associated patch.


I.     Install dnssec-tools.
       http://dnssec-tools.sourceforge.net/

II.    Follow directions in 
       dnssec-tools/apps/libspf2-1.0.4_dnssec_howto.txt to install a
       patched version of libspf2-1.0.4 from:
       http://www.libspf2.org/

III.   Download postfix postfix-2.2.3.tar.gz from
       http://www.postfix.org.
       Download the spf2 patch, postfix-libspf2-2.2.0-5.patch, from Dean
       Strik at http://www.ipnet6.org/postfix/spf/.  

IV.    
       Following the instructions that came with the patch file,
       postfix-libspf2.README, make and install postfix.

