Auth on outgoing and dkim signing

Hi all!

I finally have to get my outgoing SMTP working, and I have to DKIM-sign 
them. So, I need to get auth working, the last time I tried, in 2009, I 
simply couldn't get it working... That's a long time ago though :-)

But before I start, I still have 0.84, since the box is Debian Jessie. 
Does the dkim plugin depend on a more recent version? 

Secondly, I would like to just accept all email unauthenticated from my 
LAN, can I configure qpsmtpd to let anything from 172.22.0.0/16 go through?

Kjetil