User:Yuan/interested in the video

1. In the Video, he mentioned about email routing via DNS. The boundary mail transfer agent has to locate the target host. It uses the Domain name system (DNS) to look up the mail exchanger record for the recipient's domain (the part of the email address on the right of @). The returned Mail exchanged record contains the name of the target host.

2. He also talked about the distributed DNS. A DNS database can be partitioned into multiple zones. A zone contains the resource records with the owner names that belong to the contiguous portion of the DNS namespace. A single DNS server can be configured to host zero, one, or multiple zones. Each zone is anchored at a specific domain name referred to as the zone’s root domain. A zone contains information about all names that end with the zone’s root domain name. A DNS server is considered authoritative for a name if it loads the zone containing that name. A name within a zone can also be delegated to a different zone that is hosted on a different DNS server. Then we can delegate management of a DNS domain to a number of organizations or departments within an organization. And distribute the load of maintaining one large DNS database among multiple DNS servers to improve the name resolution performance as well as create a DNS fault-tolerant environment.

3. Some people asked Paul Mockapetris that whether domain names should be ended by country code, or some general top-level domain names like .edu, .com.......And he said use both. Then I am confused when it has both international top-level domain names and national top-level domain names, which would be in the end?