I'm having problems with hotmail. Seems as though they've introduced a new spam blocker, and it requires me to have SPF for all my domains.

Is there an easy way of bind always responding to SPF for every zone?

Something to define in named.conf?

I have hundereds of domains and i don't want to have to modify all of their zones.
Also, whats the best SPF to use?
v=spf1 mx a ?all
v=spf1 ip4: ~ all