CompTIA Network+ CH3

How can this IPv6 address be shortened? 2001:0000:0B80:0000:0000:00D3:9C5A:00CC.

Leading zeroes in a four-character hex block can be eliminated. This means our sample IP address can be written as 2001:0000:B80:0000:0000:D3:9C5A:CC. If blocks contain all zeroes, they can be eliminated and replaced by double colons (::). To avoid confusion, only one set of double colons is used in an IP address. This means our sample IP address can be written two ways: 2001::B80:0000:0000:D3:9C5A:CC 2001:0000:B80::D3:9C5A:CC 2nd one is preferred because it contains the fewest zeroes.

The first 24 bits of a MAC address are known as the ____

OUI (Organizationally Unique Identifier), which identifies the NIC's manufacturer.

How does the gateway know which local host is to receive a response from a host on the Internet?

PAT (Port Address Translation) assigns a separate TCP port to each session between a local host and an Internet host.

What are port numbers assigned to?

Processes.

DNS name servers are organized in the hierarchical structure, At the root level, 13 clusters of _____________ hold information used to locate the TLD (top-level domain) servers. These TLD servers hold information about the authoritative servers owned by various organizations.

Root servers

What are the two variations of NAT?

SNAT and DNAT

What is most often used for a TXT record?

SPF (Sender Policy Framework)—A validation system that helps fight spam by identifying the email servers allowed to send email on behalf of a domain. DKIM (DomainKeys Identified Mail)—An authentication method that uses encryption to verify the domain name of an email's sender.

What does "A (Address) record" store?

Stores the name-to-address mapping for a host. This resource record provides the primary function of DNS—to match host names to IP addresses, using IPv4 addresses.

network ID

The 32 bits are used to indicate what portion of an IP address is the network portion.

What is the primary DNS server?

The authoritative name server for the organization, which holds the authoritative DNS database for the organization's zones. This server is contacted by clients, both local and over the Internet, to resolve DNS queries for the organization's domains.

What is the secondary DNS server?

The backup authoritative name server for the organization. When a secondary DNS server needs to update its database, it makes the request to the primary server for the update; this process is called a zone transfer.

What is the third step of IPv6 AutoConfig?

The computer asks if a router on the network can provide configuration information. This message is called a RS (router solicitation). If a router responds with DHCP information in what's called a RA (router advertisement) message, the computer uses whatever information this might be, such as the IP addresses of DNS servers or the network prefix.

What is the second step of IPv6 AutoConfig?

The computer checks to make sure its IP address is unique on the network.

What is the first step of IPv6 AutoConfig?

The computer creates its IPv6 address. It uses FE80::/64 as the first 64 bits, called the prefix. Depending on how the OS is configured, the last 64 bits (called the interface ID) can be generated in two ways: The 64 bits are randomly generated The 64 bits are generated from the network adapter's MAC address—MAC addresses consist of 48 bits and must be converted to the 64-bit standard, called the EUI-64 (Extended Unique Identifier-64) standard.

classful addressing

The dividing line between the network and host portions is determined by the numerical range the IP address falls inDivided into five classes: Class A, Class B, Class C, Class D, and Class E.

What is a DNS zone?

The domains (for example, cengage.com and course.com) that the organization is responsible for managing

What is an interface ID?

The last 64 bits, or four blocks, of an IPv6 address. These 64 bits uniquely identify an interface on the local link.

What is TLD?

The last part of an FQDN (com in our example)

What are well-known ports?

They Range from 0 to 1023 and are assigned by IANA to widely used and well-known utilities and applications, such as Telnet, FTP, and HTTP.

What are registered ports?

They Range from 1024 to 49151 and can be used temporarily by processes for nonstandard assignments for increased security. Default assignments of these registered ports must be registered with IANA.

What layer utilizes Transport numbers?

Transport layer. Used to find an application.

What are the three classes of IPv6 addresses?

Unicast address, mulitcast address, and anycast address

What does a PTR (Pointer) record store?

Used for reverse lookups, which provide a host name when you know its IP address. PTR records are usually created by ISPs and stored in a specially formatted reverse lookup zone file, or reverse zone.

What is IPv6 Autoconfiguration?

When a computer automatically links to its own local IP address without any help from the DHCPv6 server.

interface

a network connection made by a node on a network

What is an interface?

a node's attachment to a link. The attachment can be physical using a network adapter or wireless connection, or logical, such as with a virtual machine.

DHCP scope

a range of IP addresses to be assigned to clients when they request an address.

In Linux systems, you configure the DHCP software by editing

a text file.

scope options

a time limit, called a lease time the default gateway's IP address the primary and secondary DNS server addresses

What is a link?

any LAN bounded by routers

At which layers do addressing methods operate?

at the Data Link, Network, Transport, and Application layers

Class A, B, and C licensed IP addresses are ....

available for use on the Internet and are therefore called public IP addresses.

Technically, a LAN, which consists of all the nodes a broadcast reaches, can be referred to as a

broadcast domain

What is a DMZ?

demilitarized zone. The area between two firewalls.

What are the two types of unicast addresses?

global address, and link local address

host name

identifies the individual computer on the network

default gateway

is the gateway device that nodes on the network turn to first for access to the outside world

domain name

matches the name of the organization's domain or network

Class D and Class E IP addresses are ...

not available for general use.

Namespace databases are stored in DNS zone files, which keep information in various types of _____.

resource records

When the host receives a request to communicate on a TCP port, it establishes or opens a

session.

A socket is open when a session ____ and closes when a session ____.

starts, ends.

What is an authoritative server?

the authority on computer names and their IP addresses for computers in their domains

What is name resolution?

the process of discovering the IP address of a host when its FQDN is known.

Why was IPv6 developed?

to improve routing capabilities and speed of communication over the established IPv4 standards and to allow for more public IP addresses on the Internet.

if packets on this network must traverse other networks where dual stacking is not used, the solution is to use ...

tunneling, which is a method of transporting IPv6 packets through or over an IPv4 network.

What are neighbors?

two or more nodes on the same link.

What is DNAT? What does it do?

(Destination Network Address Translation). hosts outside the network address a computer inside the network by a predefined public IP address. When a message sent to the public IP address reaches the router managing DNAT, the destination IP address is changed to the private IP address of the host inside the network. The router must maintain a translation table of public IP addresses mapped to various hosts inside the network.

What is DNS? What is it made up of?

(Domain Name System or Domain Name Service) It consists of: namespace—The entire collection of computer names and their associated IP addresses stored in databases on DNS name servers around the globe name servers—Computers that hold these databases, organized in a hierarchical structure resolvers—A DNS client that requests information from DNS name servers

What is ICMP>

(Internet Control Message Protocol), a lightweight protocol used to carry error messages and information about a network.

What is LDAPS?

(Lightweight Directory Access Protocol over SSL) uses SSL to encrypt its communications.

What is LDAP?

(Lightweight Directory Access Protocol)—A standard protocol for accessing network-based directories.

NAT

(Network Address Translation) is a technique designed to conserve the number of public IP addresses needed by a network.

What is NTP?

(Network Time Protocol)—A simple protocol used to synchronize clocks on computers throughout a network.

What is ping?

(Packet Internet Groper) is used to verify that TCP/IP is installed, bound to the NIC, configured correctly, and communicating with the network.

What is SMB?

(Server Message Block) —First used by earlier Windows OSes for file sharing on a network. UNIX uses a version of SMB in its Samba software, which can share files with other operating systems, including Windows systems.

What is SIP?

(Session Initiation Protocol)—A signaling protocol that is used to make an initial connection between hosts but that does not participate in data transfer during the session. After SIP establishes the connection, other protocols kick in—for example, RTP (Real-time Transport Protocol or Real-time Protocol) that transports streaming audio and video data for VoIP calls.

What is SNAT? What does it do?

(Static Network Address Translation or Source Network Address Translation), the gateway assigns the same public IP address to a host each time it makes a request to access the Internet. Small home networks with only a single public IP address provided by its ISP use SNAT.

What is TTL?

(Time to Live) field that identifies how long the record should be saved in a cache on a server

What is TFTP ?

(Trivial File Transfer Protocol)—Most commonly used by computers (without user intervention) as they are booting up to request configuration files from another computer on the local network. TFTP uses UDP, whereas normal FTP uses TCP.

What does a "AAAA (Address) record" store?

(called a "quad-A record")—Holds the name-to-address mapping for IPv6 addresses.

How do gateway devices use address translation?

A gateway device that stands between a private network and other networks substitutes the private IP addresses used by computers on the private network with its own public IP address when these computers need access to other networks or the Internet.

What is a global address?

A global address is required to access the Internet. Most begin with the prefix 2000::/3, although other prefixes are being released. The /3 indicates that the first three bits are fixed and are always 001.

What is a dual-stacked network?

A network that utilizes both IPv6 and IPv4 protocols.

static IP address

A permanent IP address that is manually assigned to a computer.

What is a recursive query?

A query that demands a resolution or the answer "It can't be found." For example, the initial request the resolver makes to the local server is a recursive query. The local server must provide the information requested by the resolver, as in "The buck stops here."

What is an iterative query?

A query that does not demand resolution. For example, when the local server issues queries to other servers, the other servers only provide information if they have it.

What is the caching DNS server?

A server that accesses public DNS data and caches the DNS information it collects. This server receives DNS queries from local network clients and works to resolve them by contacting other DNS servers for information. Caching DNS servers do not store zone files (which is why they must rely on their caches and resolution efforts), and therefore do not participate in zone transfers, which further helps to reduce network traffic on the intranet.

dynamic IP address

A temporarily assigned IP address usually provided by an ISP

subnet mask

Also called a netmask; a 32-bit number that helps one computer find another. T

What is an ip address? What layer does ip address operate?

An IP address can be used to find any computer in the world if the IP address is public on the Internet. IP address is used only at the Network layer.

What is a link local address?

An address that can be used for communicating with nodes in the same link, and is similar to an autoconfigured APIPA address in IPv4. It begins with FE80::/10. The first 10 bits of the reserved prefix are fixed (1111 1110 10), and the remaining 54 bits in the 64-bit prefix are all zeroes. Therefore, a link local address prefix is sometimes written as FE80::/64

What is a unicast address?

An address that specifies a single node on a network.

What is a process?

An application or a service that can receive data.

What is forwarding DNS server?

An optional server that receives queries from local clients but doesn't work to resolve the queries. Typically, a forwarding server will maintain its own DNS cache from previous queries, and so it might already have the information the client needs. If not, the forwarding server forwards the query to another server to resolve. Several forwarding servers might be strategically placed throughout the organization's network to reduce network traffic on slow links.

What is H.323?

Another signaling protocol used to make a connection between hosts prior to communicating multimedia data. H.323 has largely been replaced by SIP, which is easier to use.

IANA recommends that the following IP addresses be used for private networks:

10.0.0.0 through 10.255.255.255 • 172.16.0.0 through 172.31.255.255 • 192.168.0.0 through 192.168.255.255

How many bits are in an IPv6 address? How are they written?

128 bits. Written as eight blocks of hexadecimal numbers. For example, 2001:0DB8:0B80:00 00:0000:00D3:9C5A:00CC. Each block contains 16 bits

What is a subnet ID?

16 bits in a global address that is used to identify a subnet on a large corporate network.

Class D addresses begin with octets ....

224 through 239 and are used for multicast transmissions, in which one host sends messages to multiple hosts.

Class E addresses, which begin with ...

240 through 254, are reserved for research.

How many bits are in an IPv4 address? How are they written?

32 bits Written as four decimal numbers called octets. For example, 92.106.50.200

How many bits is a mac address and what are they written as?

48 bits, written as six hex numbers separated by colons, as in 00:60:8C:00:54:99

Data Link layer MAC address

A MAC address is embedded on every NIC on the globe and is assumed to be unique to that NIC.

gateway

A computer, router, or other device that a host uses to access another network

What is a firewall?

A dedicated device or software on a computer that selectively filters or blocks traffic between networks.

What is the most popular DNS server softare?

BIND (Berkeley Internet Name Domain)

______________ tools are a great way to get a look "under the hood" when something is going wrong on your network.

Command-line

What is a socket?

Consists of both a host's IP address and a process's TCP or UDP port, with a colon separting the two values. For example: 10.43.3.87:23

What is DHCPv6? What ports do DHCP servers listen on? What ports do clients receive responses on?

DHCP for IPv6

DHCP

Dynamic Host Configuration Protocol server that manages the dynamic distribution of IP addresses to devices on a network.

_______________ is one of the first places to start looking for clues

Event Viewer

The last 24 bits of a MAC address make up the ___

Extension identifier/device ID

Every host on a network is assigned a unique character-based name called the __________.

FQDN (fully qualified domain name)

What does a CNAME (Canonical Name) record store?

Holds alternative names for a host. These names can be used in place of the canonical name, which is the complete and properly formatted name, such as www.mycompany.com.

What does a TXT (Text) record store?

Holds any type of free-form text. It might contain text designed to be read by humans regarding network, server, or accounting issues.

What does a MX (Mail Exchanger) record do?

Identifies an email server and is used for email traffic.

What does a SRV (Service) record do?

Identifies the hostname and port of a computer that hosts a specific network service besides email, such as FTP or SIP.

What does a NS (Name Server) record do?

Indicates the authoritative name server for a domain. It's mostly used for delegating subdomains to other name servers.