week 4 lecture Flashcards
what is a name server?
A central database that translates names to IP addresses (or IP addresses to names)
what is a resource record?
A file containing resource information or characteristics about a zone or domain
what does DNS stand for?
Domain Name System
what is the role of Internet’s Domain Name System (DNS)
Associates an IP address (such as 204.21.112.110) with an actual name (such as server1)
what is the goal of DNS
to decentralize administration
what are the characteristics of a local DNS server
-Can handle cached hostname requests
-Doesn’t contain information on every hostname on the Internet
-Forwards requests for unknown hostnames to a forwarder
what is a forwarder?
-A type of DNS server
-Forwarder’s job is to handle off-site requests generated at the system known as “localhost”
what is caching?
A feature that stores DNS queries on the local site for fast hostname–to–IP address resolution
what is a root DNS server?
-Centrally controlled public DNS servers
-Control the Internet’s top-level domains (TLDs)
how is a DNS database structured?
as an inverted tree
what are the characteristics of a DNS database
-Also known as domain namespace
-Root at top of the tree
-Top Level Domain’s beneath it
-Nodes (leaves) of the tree are called domains and have labels
-Domain names are derived from node labels
-Each level of hierarchy is separated by dots in domain name
how many independent root servers are there worldwide?
13
what is a root server made up of?
a cluster of servers distributed around the world
what is a DNS zone?
A portion of the DNS namespace that has been delegated to other servers/administrators
what is a zone file?
Stores the data for a zone
