Setting up SPF and DKIM
For SPF I use this wizard, http://old.openspf.org/wizard.html . It works well with DJBDNS.
Example SPF string:
v=spf1 ip4:192.168.2.125/30 a mx:mail.example.com include:example.org ~all
'example.com:v=spf1 ip4\072192.168.2.125/30 a mx\072mail.example.com include\072example.org ~all:3600
This is more of a pain and adds extra mail server load because the mail server has to be patched to support DKIM signing and each message must be signed as it passes through the server. I have not figured this out yet for qmail or MS Exchange.