Subscribers Blacklist

I’m testing Knews on my website, really great plugin!

Now I have a question: some subscribers subscribes using temporary email service and so do create fake email subscirbed.

How can I put this emails addresses or domains in a blacklist in order to avoid subscriptions?

For example *@temporary__email.com or exact@e__mail.com

Tanks,
Matteo.

http://ww.wp.xz.cn/extend/plugins/knews/