Ask HN or PG: Is there a list of HN banned domains?

I just submitted a story I ran across yesterday from Valleywag. It was immediately marked as dead, and I assume this is a result of an automatic ban. Is there any list of banned domains to consult when a post is auto-dead? Or is this intentionally not listed?

The post in question: https://news.ycombinator.com/item?id=6225312