Mike Meyers' CompTIA Network+ - Chapter 9: Network Naming

AAAA records

("quad A" when spoken) are the equivalent of A records, but they hold IPv6 addresses.

CNAME record

A Canonical Name record within DNS, used to provide an alias for a domain name.

DNS Records

Address Mapping records. Specifies IP address (IPv4) for given host. A records are used for conversion of domain names to corresponding addresses.

A record

An A Record maps a hostname to one or more IP addresses for IPv4

Forward Lookup

Finds the IP address for a given hostname

Public DNS Servers

Name servers specifically set up so that anyone can use them for free.

NS record

Records that list the DNS servers for a Web site.

MX record

Records within DNS servers that are used by SMTP servers to determine where to send mail.

SOA record

Start of Authority record. This record identifies the primary name server for the zone. The SOA record contains the host name of the server responsible for all DNS records within the namespace, as well as the basic properties of the domain.

Server Message Block (SMB)

A Microsoft developed protocol used to provide shared access to files printers and other network resources. It runs on port 445.

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.

Domain Name System (DNS)

Internet service that translates domain names into IP addresses.

SRV record

Locator record within DNS that allows clients to locate an Active Directory domain controller or global catalog.

recursive lookup

Occurs when a router has to perform multiple lookups in a routing table before forwarding a packet.

resolver cache

Storage for recently resolved DNS data on a DNS client; used so that clients don't have to perform DNS lookups if host were resolved recently.

fully qualified domain name (FQDN)

The complete domain name of an Internet computer, such as www.CIWcertified.com.

ipconfig

The utility used to display TCP/IP addressing and domain name information in the Windows client operating systems.

reverse lookup

To find the host name when you know a computer's IP address. The Nslookup command can perform a reverse lookup.

host name

first portion of a web name; often "www."

Time to Live (TTL)

the maximum amount of time a packet is allowed to circulate through a network before it is destroyed

NetBIOS over TCP/IP (NetBT)

A Microsoft-created protocol that enabled NetBIOS naming information to be transported over TCP/IP networks. The result is that Microsoft naming services can operate on a TCP/IP network without the need for DNS services.

TXT record

A TXT record is used to associate any arbitrary text with a hostname. This record type is only used in specific cases such as Domain Keys Identified Mail, used as a method to detect email spoofing.

Active Directory

A Windows server directory database and service that is used in managing a domain to allow for a single point of administration for all shared resources on a network, including files, peripheral devices, databases, Web sites, users, and services.

tracert/traceroute

A command similar to ping that also shows the path between the two devices. Use tracert on Windows and traceroute on Linux and Mac OS.

name server

A computer dedicated to providing responses to requests for Domain Name information.

Authoritative Name Server

A computer of the Domain Name System that knows for its domain the IP address of all computers and authoritative name servers in it.

Hierarchical Name Space

A naming scheme where the full name of each object includes its position within the hierarchy. An example of a hierarchical name is www.totalseminars.com, which includes not only the host name, but also the domain name. DNS uses a hierarchical name space scheme for fully qualified domain names (FQDNs).

HOSTS file

A plaintext file configured on a client machine containing a list of IP addresses and their associated host names, which can be used for host name resolution as an alternative to DNS.

top-level domain server

A set of DNS servers—just below the root servers—that handle the top-level domain names, such as .com, .org, .net, and so on.

secondary name server

A type of DNS server that gets its zone data from another DNS name server that has authority in that zone.

A Record vs CNAME record

An A Record maps a hostname to one or more IP addresses, while the CNAME record maps a hostname to another hostname.

primary name server

An authoritative name server that is queried first on a network when resolution of a name that is not already cached is requested. Also called master name servers.

root

An organ in vascular plants that anchors the plant and enables it to absorb water and minerals from the soil.

Resolvers

Any hosts on the internet that need to look up domain name information

serial fields

As an administrator, you add this data to the primary name server. The primary name server then advances a special value called a serial field that secondary name servers regularly check. If the secondary servers see that their serial field is lower than the one on the primary server, they request a zone transfer of the DNS zone from the primary server

netstat command

Can display a variety of information about IP-based connections on a Windows or UNIX host.

Domain Information Groper (DIG)

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

zone

DNS (Domain Name System) is vital to IP networking, whether on the Internet or within the smallest of networks. DNS functions as a hierarchical naming system for computers on a network. DNS is split into two kinds of server: resolvers that end-user computers use to ask to translate DNS names to IP addresses, and name servers that hold the actual name and IP address DNS records in a database called a zone.

zone transfer

In DNS, the act of copying a primary name server's zone file to the secondary name server to ensure that both contain the same information.

DNS Caching

In order to improve DNS delay performance and to reduce the number of DNS messages this method is used

Internet Corporation for Assigned Names and Numbers (ICANN)

It has the authority to create new TLDs(Top Level Domains.) ICANN has added hundreds of generic TLDs, such as .biz for businesses and .rodeo for—you guessed it—the rodeo industry.

NetBIOS/NetBEUI

Microsoft developed networking protocol from the 1980's that incorporated a naming convention that used broadcasts for naming resolutions. Windows used a simple networking protocol for a long time, called NetBIOS/NetBEUI. It was designed primarily for sharing files and folders in a local network. The protocol didn't work when scaled up because it wasn't routable and relied too much on broadcasts.

Tracert vs Traceroute

On a Windows machine, this command is called tracert; on Linux and Mac, it's called traceroute. Traceroute and tracert largely function in the same way—they map the route data takes from one point in a network to a specific IP server.

top-level domain (TLD) name

The extension such as .com or .edu that follows the host name and indicates the type of group or institution to which the site belongs.

DNS Root Servers

The highest in the hierarchy of DNS servers running the Internet.

name resolution

The process by which an IP host discovers the IP address associated with a hostname, often involving sending a DNS request to a DNS server, with the server supplying the IP address used by a host with the listed hostname.

PTR record

Which DNS record is used to allow a server to resolve an IP address to a fully-qualified domain name (FQDN)?

DNS server

a computer or a group of computers that maintain a database to enable a computer to know the IP address of a URL

nslookup

a tool used to query the DNS system to find the IP addresses for domain names, and vice versa

ping

send a message from one computer to another to check whether it is reachable and active