Global Name Server placement

Having more than one name server (a DNS record type) set to your domain name provides redundancy, and works for ensuring your website's availability at all times. If, for some reason, your primary name server cannot be reached at a given time, your visitor's DNS resolution request is routed to the secondary server set for your domain. If, however, this one is unreachable too, the request is routed down the whole chain of name servers until the requested IP address matching the domain name your visitor types in the address bar is located by the DNS server.