The stability is excellent and the product is very mature.
Palo Alto Networks DNS Security is praised for its excellent stability and valuable features including DNS filtering, DNSSEC, and the domain generation algorithm. Scalability is rated highly but identified for improvement, along with issues of DNS client disconnections and legitimate traffic blockage. Pricing is a concern, viewed as expensive compared to Infoblox or Cisco Umbrella. Though the support team is knowledgeable, customer service faces criticism for outsourced support and slower response times.