Section 9: Network Services Flashcards
What is the Dynamic Host Configuration Protocol (DHCP)?
Assigns devices with IP addresses and also provides them a subnet mask, default gateway, and DNS server.
Operates over ports 67 & 68 using UDP
What is a DHCP Scope?
A list of valid IP addresses that are available for assignment or lease to a client computer or endpoint device on a given subnet
What is a DHCP Reservation?
A permanent IP address from a DHCP server to a specific device on a network
What is the average lease time for DHCP servers?
24 hours
What is a DHCP Relay?
Forwards DHCP packets between clients and servers
What is an IP Helper/UDP Forwarding?
Forwards several different kinds of UDP broadcasts across the router and can be used in conjunction with the DHCP relay
What is a Domain Name System (DNS)?
Helps a network client find a website using human-readable hostnames instead of numeric IP addresses
What is an A Record?
A record used for IPv4 addresses
What is a AAAA Record?
A record used for IPv6 addresses
What is a CNAME Record (Canonical Name Record)?
Used instead of an A record or AAAA record if you want to point a domain to another domain name or subdomain
What is an MX Record (Mail Exchange Record)?
Used to direct emails to a mail server
What is a SOA Record (Start of Authority Record)?
Used to store important information about a domain or zone
What is a PTR Record (Pointer Record)?
Used to correlate an IP address with a domain name
The opposite of an A Record
What is a TXT Record (Text Record)?
Used by domain administrators to add text into the domain name system
What is a SRV Record (Service Record)?
Used to specify a host and port for a specific service
What is a NS Record (Name Server Record)?
Used to indicate which DNS name server is the authoritative one for a domain
What is a Root DNS server? What are some examples?
Answers requests in the root zone.
.com, .org, .net
What are examples of geographic hierarchy?
.uk for United Kingdom, .fr for France, .it for Italy
What is a Zone Transfer?
Sharing of information between DNS servers about which domain names they have and their associated IP addresses
What is an Internal DNS?
Allows cloud instances on the same network access each other using internal DNS names
What is an External DNS?
Records created around the domain names from a central authority and used on the public Internet
What is an Authoritative Name Server?
A type of DNS server that stores all the DNS records for a given domain
What is Time to Live (TTL)?
Tells the DNS resolver how long to cache a query before requesting a new one
What is DNS Caching?
Makes a local copy of every DNS entry it resolves as you connect to websites
