1. A method for registering user endpoint devices via a network edge device in a next generation network, the method comprising: at a domain name system load balancer, protecting a domain name system server by limiting to a first threshold rate an overall query rate of domain name system queries sent to the domain name system server; at the domain name system load balancer, monitoring a rate of domain name system queries for resolving a domain name of a particular target network edge device in the next generation network; receiving from the user endpoint devices a flow of domain name system queries, each query of the flow being for resolving the domain name of the same particular target network edge device for use in registering in the next generation network; if the rate of domain name system queries for resolving the domain name of the particular target network edge device is below a second threshold rate lower than the first threshold rate, then forwarding the flow of domain name system queries to the domain name system server; if the rate of domain name system queries is above the second threshold rate for the target network edge device, then throttling the flow of domain name system queries.