Juniper Exam JN0-335 Topic 7 Question 23 Discussion

The DNS ALG is an application layer gateway that handles data associated with locating and translating domain names into IP addresses. It runs on port 53 and monitors DNS query and reply packets. Two statements about the DNS ALG that are correct are:

The DNS ALG supports DDNS: DDNS is Dynamic DNS, which is a method of updating DNS records in real time to reflect changes in network configurations or hostnames. The DNS ALG can process DDNS messages differently from DNS messages and perform address translation in the query part of the message.

The DNS ALG performs DNS doctoring: DNS doctoring is a technique of modifying the DNS reply packets to replace the original IP addresses with translated IP addresses that are suitable for the destination network. This allows the clients to access servers that are located behind NAT devices or in different networks.