Chapter 9 Guide to Managing and Troubleshooting Networks

Dynamic DNS (DDNS)

A protocol that enables DNS servers to get automatic updates of IP addresses of computers in their forward lookup zones, mainly by talking to the local DHCP server.

A DNS forward lookup zone uses a(n) ________ for individual host records.

A-record

How DNS works:

DNS root servers delegates name resolution to other DNS servers. Below the root servers are top-level domain servers that handle top level domain (TLD) names like .com, .edu, .gov. Then the top level domain servers delegate to smaller second level DNS servers which support individual computers

To connect to systems on the Internet using domain names, your network needs the name of at least one _______________.

DNS server

Secondary zones

Created on other DNS servers to act as backups to the primary zone.

Primary zones

Created on the DNS server that will act as the primary name server for the zone

Which of the following are needed for e-mail clients to find their e-mail servers, FTP clients to find their file servers, and Web browsers to find Web servers?

DNS Server

Name Servers have 3 key players:

DNS Server Zone Record

The term _______________ refers to networks that use DNS belonging to the same DNS system.

DNS Tree

Fully Qualified Domain Name (FQDN)

Domain name that specifies its exact location in the tree hierarchy of the domain names system. Ex: www.google.com

workgroup

In windows, it is a name that organizes a group of computers

Server Message Block (SMB)

Ran on top of NetBT to support sharing files and folders. Uses NetBIOS names to support sharing and access TCP port 445

NS record

Records that list the DNS servers for a website

Hierarchical Name Space

an imaginary tree structure of all the possible names that could be used within a single system More flexible than flat name space, allows for more than one item to have the same name

Active Directory

an organization of related computers that share one or more windows domains.

What type of DNS servers do not have any forward lookup zones and will resolve names of systems on the Internet for a network but are not responsible for telling other DNS servers the names of any clients?

cache-only servers

Start of Authority (SOA) record

defines the primary name server in charge of the forward look up zone

Which of these terms are frequently used interchangeably?

domain and subdomain

AAAA records

equivalent of A-records

MX records

exclusively used by SMTP servers to determine where to send mail

TXT record

freeform type of record that can be used for anything. Allow text to be added to a forward look up zone

The _______________ gets precedence over querying a DNS server.

hosts

What file can you modify to resolve a name that takes effect regardless of the DNS server records?

hosts

Zone

a container for a single domain that gets filled with records

DNS Forwarding

a dns server configured to forward any dns request for which the dns server is not authoritative

windows domain

a group of computers controlled by a computer running windows server

Record

a line in the zone data that maps the FQDN to an IP address

secondary DNS server

A DNS server that is a backup to a primary DNS server and therefore is not authoritative.

Which of the following are valid DNS record entry types?

.com

DNS Process

1. Local DNS server receives a request for the IP address for www.microsoft.com (example) 2. Checks resolver cache for a name 3. If not there, DNS server contacts the DNS root servers 4. Root servers sends local DNS to the top-level domain server for .com addresses 5. .com server doesnt know the address but it knows the address of microsoft.com dns server, it sends that IP to your local server 6. local server contacts microsoft.com dns server and gets the IP

Why is NetBIOS and NetBEUI not suitable for large networks?

1. No logical addressing 2. Broadcasting made it unacceptable for large networks

What port does DNS use?

53

primary (master) DNS server

A DNS server that is used as the main server from which to administer a zone, such as updating records in a forward lookup zone for a domain. A primary DNS server is also called the authoritative server for that zone.

Reverse Lookup Zone

A DNS setting that resolves IP addresses to FQDNs

DNS Resolver Cache

A cache used by Windows DNS clients to keep track of DNS information.

Authoritative Name Server

A computer of the Domain Name System that knows the host names on the domain and their corresponding IP's

Flat Name Space

A naming convention used by host files that gives each device only one name that must be unique

External DNS Server

Any DNS server not internal to an organization

Public DNS Servers

Any dns server that resolves legitimate internet domains and requests for FQDN

How do authoritative DNS servers and cache-only DNS servers differ?

Authoritative DNS servers store IP addresses and FQDNs of systems for a particular domain or domains, whereas cache-only DNS servers do not store any static FQDNs because they are only used to talk to other DNS servers to resolve IP addresses.

The single DNS server that has a list of all the host names on the domain and their corresponding IP addresses—and actively distributes that zone list—is the _______________.

Authoritative server

Domain Information Groper (DIG)

Command-line tool in non-Windows systems used to diagnose DNS problems. Is similar to nslookup

What do DNS servers use to help resolve FQDNs to IP addresses?

Forward lookup zones

nslookup

Gives the name and IP address of the default DNS server.

Internet Corporation for Assigned Names and Numbers (ICANN)

Has the authority to create new TLD

DNS tree root

Holding area to which all domains connect

hosts file

Legacy naming system that contained a list of IP addresses for every computer on the Internet. Used when the Internet was simpler

Canonical Name (CNAME)

Maps multiple cononical names (aliases) to an A record

NetBIOS/NetBEUI

Microsoft developed naming protocol made in the 1980's. When a computer booted up, it broadcast its name along with its MAC address

Domain Name System (DNS)

Name resolution protocol used by tcp/ip networks Uses UDP port 53 and sometimes tcp 53

Private DNS server

Private servers that are invisible to the internet

What do DNS servers use to help resolve IP addresses to DNS names?

Reverse lookup zones

NetBIOS over TCP/IP (NetBT)

Runs NetBIOS on top of TCP/IP. Uses TCP port 137/139 and UDP port 137/138

Top level domain servers

Second level in the DNS hierarchy Handle top level domain names like .com, .edu, .gov, etc Delegate to smaller second level dns servers

The _______________ protocol originally ran on top of NetBT, but today runs by itself and uses port 445.

Server Message Block (SMB)

Second level DNS server

Support individual compuers

Cached Lookup

The list kept by a DNS server of IP addresses it has already resolved, so it won't have to re-resolve an FQDN it has already checked.

Pointer Record (PTR)

The record created from a reverse lookup zone

forward lookup zone

The storage area in a DNS server to store the IP addresses and names of systems for a particular domain or domains.

root servers

Top of the DNS hierarchy 13 of them around the world

Which of the following are valid DNS record entry types?

a ns soa

DNS Server

a computer running DNS server software

A helpful command that displays TCP/IP naming information is _______________.

ipconfig

Running which of the following commands clears the local cache of DNS entries?

ipconfig/flushdns

A-Record

maps a domain name to the IP address

Running what command gives you the IP address and the name of your system's default DNS server?

nslookup

The _______________ command is used to establish connectivity.

ping

To avoid having to re-resolve an FQDN that it has already checked, a Windows DNS server keeps a list of IP addresses it has already resolved, called _______________.

resolved cache list

DNS servers

server program that allows DNS systems to delegate work

IP Address Management (IPAM)

software that includes at minimum a DHCP server and a DNS server that work together to administer IP addresses

What does adding a caching-only DNS server accomplish on your network?

speeds up dns resolution

Which of the following ports is used by Windows to support pre-DNS naming protocols?

tcp 137

You can use the diagnostic utility called _______________ in Windows to trace the progress of an ICMP packet between your system and a remote computer.

traceroute

Folders with subfolders on a system, like domain names with subdomains, are said to have a structure resembling what?

tree