As a continuation of the development process and increasing the level of stability, security and reliability of Saudi domain names (.sa & .السعودية), SaudiNIC/CST has improved the overall distribution of the Saudi ccTLD DNS servers. This includes adding another Anycast provider to the list of secondary servers for the purpose of increasing the footprint regionally and internationally of Saudi domain names. It is worth to mention that, currently, there are five copies of the Saudi ccTLD DNS servers within the Kingdom. Two of them are hosted in CST networks. Another two are hosted in STC premises. While the fifth one is hosted by the Internet Services Unit of KACST. Additionally, there are another two copies that are hosted worldwide that are using Anycast technology with around 150 instances for the purpose of minimizing DOS attacks.
Attached a figure depicts the distribution of Saudi ccTLD DNS servers around the world (7 secondary instances with additional 150 anycast instances):http://www.dnssec.sa/)