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
