Lesson 12: Deploying and Configuring the DNS Service Flashcards Preview

Server 2012 MOAC 70-410 > Lesson 12: Deploying and Configuring the DNS Service > Flashcards

Flashcards in Lesson 12: Deploying and Configuring the DNS Service Deck (70)
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1
Q

Host table

A

Local file matching IPs to hostnames. No longer actively used, but still possible

2
Q

Name resolution

A

Using DNS servers to convert host names into IP addresses

3
Q

3 elements of DNS

A

DNS name space
Name Servers
Name resolvers

4
Q

DNS Name Space

A

Tree-structured name space – each branch of the tree IDs a domain. Each domain contains a collection of resource records, which contain host names & IPs.

5
Q

Name Servers

A

DNS server – application that maintains info about the domain tree structure and authoritiative info about one or more specific domains in that structure.

6
Q

Resolvers

A

Client program that generates DNS queries and sends them to a DNS server for fulfillment.

7
Q

Each host is uniquely identified by what?

A

A host name and domain name combination.

8
Q

Examples of top level domains

A

.com, .net. .org etc

9
Q

What is the second level domain in this host name:

www.google.com

A

google
www is the host name
com is the TLD

10
Q

FQDN

A

Fully qualified domain name - complete DNS name for a computer.
Host name
second-level domain name
top-level domain name

11
Q

What is the authoritative source for a domain?

A

The DNS server(s) responsible for maintaining that domain’s resource records

12
Q

Root Name Servers

A

Highest-level DNS servers in the entire namespace. Maintain information about the top-level domains.
Ultimate source for allDNS info.

13
Q

gTLDs

A

Six Generic top level domains, at a level directly below root name servers. There are more now, but these are what we started with
.com, .edu, etc

14
Q

Name the gTLDs

A
com
edu
gov
mil
net
org
15
Q

gTLD use: com

A

commercial orgs

16
Q

gTLD use: edu

A

four-year degree-granting ed institution in N. America

17
Q

gTLD use: gov

A

US government institutions

18
Q

gTLD use: mil

A

US military institutions

19
Q

gTLD use: net

A

Networking organiations

20
Q

gTLD use: org

A

Noncommercial orgs

21
Q

Which gTLDs do you need some sort of certification to obtain

A

edu
gov
mil

22
Q

Which gTLDs can you get without any special process

A

com
org
net

23
Q

ICANN

A

Internet Corporation for Assigned Names and Numbers

Responsible for accreditation of domain name registrars and ratification of new top-level domains.

24
Q

In the DNS hierarchy, which level has no hosts?

A

The TLD and root levels do not have hosts outside of the DNS servers that exist to point other DNS servers in the right direction.

25
Q

ccTLD

A

Country code TLDs

Two-letter TLDs for specific countries in their own language.

26
Q

IANA

A

Internet Assigned Numbers Authority

Department of ICANN

27
Q

What is the ccTLD for the United States

A

.us

28
Q

Who administrates the US ccTLD?

A

Information Sciences Institute of the University of Southern California

29
Q

What is the second level domain in this URL?

www.google.com

A

Google

30
Q

How many DNS servers must you provide a registrar to maintain a second level domain?

A

2

31
Q

What is the max size of a second-level domain name?

A

63 characters

32
Q

What is the max size of an entire FQDN?

A

255 characters

33
Q

Which transport layer protocol does DNS use

A

UDP

34
Q

What port does DNS operate?

A

53

35
Q

Five sections of a DNS message

A
Header
Question
Answer
Authority
Additional
36
Q

DNS message section: header

A

Contains info about the nature of the message

37
Q

DNS message section: question

A

Information requested from the destination server

38
Q

DNS message section: answer

A

Contains resource records supplying the information requested in the question section

39
Q

DNS message section: authority

A

contains resource records pointing to an authority for the information requested in the question section

40
Q

Every DNS message type has a header, but the remaining sections only appear if

A

There are data to put in them.

These sections are not always relevant.

41
Q

DNS message section: additional

A

contains resource records with additional info in response to the question section

42
Q

A DNS message can contain more than one what?

A

More than one of each section.

43
Q

What happens if a dns message is too large to fit in a UDP datagram?

A

The two systems establish a standard TCP connection over port 53 to transmit the data

44
Q

How do local DNS servers speed to process of resolving IPs from hostnames?

A

Caching the IPs of a FQDN.
Caching the IPs of a TLD authoritative server and the IPs of second-level domain authoritative servers, saving steps for the next similar requests

45
Q

Negative Caching

A

When a DNS server retains info about names that do not exist in a domain.

This speeds the process the next time a user attempts to resolve a hostname that does not exist – DNS does not need to start all over again at the root name server

46
Q

TTL

A

Time to live.

The max time data can be cached on a DNS server

47
Q

Who specifies TTL?

A

Admins of the authoritative DNS server for a domain

48
Q

Referral

A

The process by which one DNS server sends a name resolution request to another dns server.

49
Q

Two types of name resolution requests

A

Recursive query

iterative query

50
Q

DNS Forwarder

A

One server that functions as a ‘proxy’ for all DNS requests, to another DNS server.

51
Q

Reverse name resolution

A

Convert an IP into a DNS name

52
Q

What service does reverse name resolution use?

A

in-addr.arpa

…Which has four sub-sub domains able to represent the first three octets of every IP address

53
Q

What are the bare minimum capabilities of a DNS server

A

Receiving queries

Sending queries to other DNS servers

54
Q

caching-only server

A

A DNS server that is not authoritative for any domain. Just receives requests and sends those requests to other DNS servers

55
Q

Dynamic update standards for DNS

A

Allows a DHCP server to notify a DNS server that an address has been changed and tell the DNS server how to modify its records

56
Q

Zone

A

administrative entity you create on a DNS server to represent a discrete portion of the DNS namespace

57
Q

Three types of zones

A

primary
secondary
stub

58
Q

Primary zone

A

The primary source for information at a given zone. Maintains an active database locally.

59
Q

Secondary zone

A

The secondary source of info at a given zone. Must get its information from the primary zone.

60
Q

Stub zone

A

Only a source of information on the authorities of this zone.

61
Q

7 types of resource records used by DNS servers

A
SOA
NS
A
AAAA
PTR
CNAME
MX
62
Q

Resource Record: SOA

A

Start of Authority
Indicates that the server is the best authoritative source for data concerning the zone. Each zone must have a SOA record. Only one SOA record per zone

63
Q

Resource Record: NS

A

Name Server
IDs a DNS server functioning as an authority for the zone. Each DNS server (primary or secondary) in a zone must be represented by an NS record.

64
Q

Resource Record: A

A

Address

Provides a name-to-address mapping that supplies IPv4 address for a DNS name.

65
Q

Resource Record: AAAA

A

Provides a name-to-address mapping that supplies IPv6 address for a specific DNS name.

66
Q

Resource Record: PTR

A

Pointer

Provides address-to-name mapping that supplies DNS name for address in the in-addr.arpa domain.

67
Q

Resource Record: CNAME

A

Canonical Name

Creates an alias that points to the canonical name (the “real” name) of a host identified by an A record.

68
Q

Resource Record: MX

A

Mail Exchanger

IDs a system that directs email traffic sent to an address in the domain to the individual recipient

69
Q

Root Hints

A

Names an addresses of multiple root name servers, often preconfigured on a DNS server

70
Q

How many root name servers are there?

A

13