network fundamentals ch 11
Loopback addresses
(127.0.0.0 /8 or 127.0.0.1 to 127.255.255.254) are more commonly identified as only 127.0.0.1, these are special addresses used by a host to direct traffic to itself. For example, it can be used on a host to test if the TCP/IP configuration is operational
Subnet a /24 Network prefix length
/25 /26 /27 /28 /29 /30
Subnet Masks on Octet Boundaries Prefix Length
/8 /16 /24
In digital logic
1 represents True and 0 represents False. When using an AND operation, both input values must be True (1) for the result to be True (1).
Subnet Address (256 Possible Subnets)
10.0.0.0/16 10.1.0.0/16 10.2.0.0/16 10.3.0.0/16 10.4.0.0/16 10.5.0.0/16 10.6.0.0/16 10.7.0.0/16 10.255.0.0/16
Subnetting Network 10.0.0.0/8 using a /24 Prefix Subnet Address
10.0.0.0/24 10.0.1.0/24 10.0.2.0/24 10.0.255.0/24 10.1.0.0/24 10.1.1.0/24 10.1.2.0/24 10.100.0/24 10.255.255.0/24
Subnetting Network 10.0.0.0/8 using a /24 Prefix host range
10.0.0.1 - 10.0.0.254 10.0.1.1 - 10.0.1.254 10.0.2.1 - 10.0.2.254 10.0.255.1 - 10.0.255.254 10.1.0.1 - 10.1.0.254 10.1.1.1 - 10.1.1.254 10.1.2.1 - 10.1.2.254 10.100.0.1 - 10.100.0.254 10.255.255.1 - 10.2255.255.254
Host-A has the IPv4 address and subnet mask: 10.5.4.100 255.255.255.0. What is the network address of Host-A?
10.5.4.0
Host-A has the IPv4 address and subnet mask: 172.16.4.100 255.255.0.0. What is the network address of Host-A?
172.16.0.0
Host-A has the IPv4 address and subnet mask: 172.16.4.100 255.255.0.0. Which of the following IPv4 addresses would be on the same network as Host-A? (Choose all that apply)
172.16.4.99 172.16.0.1
Host-A has the IPv4 address and subnet mask: 192.168.1.50 255.255.255.0. Which of the following IPv4 addresses would be on the same network as Host-A? (Choose all that apply)
192.168.1.1 192.168.1.100
Subnet a /24 Network Subnet Mask
255.255.255.128 255.255.255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252
An IPv4 address is a
32-bit hierarchical address that is made up of a network portion and a host portion.
/25 row
Borrowing 1 bit from the fourth octet creates 2 subnets supporting 126 hosts each.
/26 row
Borrowing 2 bits creates 4 subnets supporting 62 hosts each.
/27 row
Borrowing 3 bits creates 8 subnets supporting 30 hosts each.
/28 row
Borrowing 4 bits creates 16 subnets supporting 14 hosts each.
/29 row
Borrowing 5 bits creates 32 subnets supporting 6 hosts each.
/30 row
Borrowing 6 bits creates 64 subnets supporting 2 hosts each.
RFC divided the unicast ranges into specific classes as follows:
Class A (0.0.0.0/8 to 127.0.0.0/8) Class B (128.0.0.0 /16 - 191.255.0.0 /16) Class C (192.0.0.0 /24 - 223.255.255.0 /24)
Class A (0.0.0.0/8 to 127.0.0.0/8)
Designed to support extremely large networks with more than 16 million host addresses. Class A used a fixed /8 prefix with the first octet to indicate the network address and the remaining three octets for host addresses (more than 16 million host addresses per network).
Class C (192.0.0.0 /24 - 223.255.255.0 /24)
Designed to support small networks with a maximum of 254 hosts. Class C used a fixed /24 prefix with the first three octets to indicate the network and the remaining octet for the host addresses (only 254 host addresses per network).
Class B (128.0.0.0 /16 - 191.255.0.0 /16)
Designed to support the needs of moderate to large size networks with up to approximately 65,000 host addresses. Class B used a fixed /16 prefix with the two high-order octets to indicate the network address and the remaining two octets for host addresses (more than 65,000 host addresses per network).
RIPE NCC (reseaux IP europeens network coordination centre)
Europe, the middle east and central Asia
multicast clients.
Hosts that receive particular multicast packets
typical enterprise network:
Intranet DMZ
three types of IP addresses:
Network address Host addresses Broadcast address
Which organization or group of organizations receives IP addresses from IANA and is responsible for allocating these addresses to ISPs and some organizations?
RIRs
IPv4 host address (192.168.10.10)
The IPv4 address of the host in dotted decimal and binary formats.
ANDing.
The actual process used to identify the network portion and host portion is
Network address (192.168.10.0)
The logical AND operation between the IPv4 address and subnet mask results in an IPv4 network address shown in dotted decimal and binary formats.
Subnet mask (255.255.255.0)
The subnet mask of the host in dotted decimal and binary formats.
First host address -
This first host within a network has all 0 bits with the last (right-most) bit as a 1 bit. In this example it is 192.168.10.1/24.
DMZ
This is part of the company's network containing resources available to the internet such as a web server. Devices in the DMZ use public IPv4 addresses these devices need to be publicly accessible from the internet, the devices in the DMZ require public IPv4 addresses.
Intranet
This is the internal part of a company's network, accessible only within the organization. Devices in the intranet use private IPv4 addresses.
IPv4 address -
This is the unique IPv4 address of the host.
Subnet mask-
This is used to identify the network/host portion of the IPv4 address.
Last host address
This last host within a network has all 1 bits with the last (right-most) bit as a 0 bit. In this example it is 192.168.10.254/24.
A unicast packet has
a destination IP address that is a unicast address which goes to a single recipient.
Broadcast transmission refers to
a device sending a message to all the devices on a network in one-to-all communications.
large broadcast domain is
a network that connects many hosts. A problem with a is that these hosts can generate excessive broadcasts and negatively affect the network.
multicast packet is
a packet with a destination IP address that is a multicast address. IPv4 has reserved the 224.0.0.0 to 239.255.255.255 addresses as a multicast range.
broadcast address is an
address that is used when it is required to reach all devices on the IPv4 network. has all 1 bits in the host portion, as determined by the subnet mask. In this example, the network address is 192.168.10.255/24. A broadcast address cannot be assigned to a device.
AfriNIC-African Network Information Center
africa region
network address is
an address that represents a specific network. A device belongs to this network if it meets three criteria: It has the same subnet mask as the network address. It has the same network bits as the network address, as indicated by the subnet mask. It is located on the same broadcast domain as other hosts with the same network address.
Host addresses
are addresses that can be assigned to a device such as a host computer, laptop, smart phone, web camera, printer, router, etc. can have any combination of bits in the host portion except for all 0 bits (this would be a network address) or all 1 bits (this would be a broadcast address).
A source IP address can only
be a unicast address, because the packet can only originate from a single source. This is regardless of whether the destination IP address is a unicast, broadcast or multicast.
device with a private IPv4 address is not
directly accessible from another device across the internet, the IETF does not consider private IPv4 addresses or NAT as effective security measures.
A broadcast domain
identifies all hosts on the same network segment.
ARIN (American Registry for Internet Numbers)
north america region
10.55.3.168
private
172.16.30.30
private
172.16.35.2
private
192.168.11.5
private
192.168.3.5
private
Which two statements are correct about private IPv4 addresses? (Choose two.)
private IPv4 addresses are assigned to devices within an organizations intranet (internal network)
broadcast packet must be
processed by all devices in the same broadcast domain
IPv4 uses broadcast packets. However,
there are no broadcast packets with IPv6.
A default gateway IPv4 address is required
to reach remote networks and DNS server IPv4 addresses are required to translate domain names to IPv4 addresses
To create subnets
you must borrow bits from the host portion of the IPv4 address of the existing internetwork. Starting from the left to the right with the first available host bit, borrow a single bit at a time until you reach the number of bits necessary to create 1000 subnets
Link-local addresses
(169.254.0.0 /16 or 169.254.0.1 to 169.254.255.254) are more commonly known as the Automatic Private IP Addressing (APIPA) addresses or self-assigned addresses. They are used by a Windows DHCP client to self-configure in the event that there are no DHCP servers available. can be used in a peer-to-peer connection but are not commonly used for this purpose.
Subnetting Network Host Range (65,534 possible hosts per subnet)
10.0.0.1 - 10.0.255.254 10.1.0.1 - 10.1.255.254 10.2.0.1 - 10.2.255.254 10.3.0.1 - 10.3.255.254 10.4.0.1 - 10.4.255.254 10.5.0.1 - 10.5.255.254 10.6.0.1 - 10.6.255.254 10.7.0.1 - 10.7.255.254 10.255.0.1 - 10.255.255.254
Subnetting Network 10.0.0.0/8 using a /24 Prefix broadcast
10.0.0.255 10.0.1.255 10.0.2.255 10.0.255.255 10.1.0.255 10.1.1.255 10.1.2.255 10.100.0.255 10.255.255.255
Subnet a /24 Network # of subnet
2 4 8 16 32 64
Subnet Mask
255.0.0.0 255.255.0.0 255.255.255.0
subnetting
The solution is to reduce the size of the network to create smaller broadcast domains in a process
Private addresses are defined
in RFC 1918 and sometimes referred to as RFC 1918 address space.
multicast group each
is represented by a single IPv4 multicast destination address.
A limited broadcast
is sent to 255.255.255.255. By default, routers do not forward broadcasts.
The prefix length is
is the number of bits set to 1 in the subnet mask. It is written in "slash notation", which is noted by a forward slash (/) followed by the number of bits set to 1.
LACNIC - (regional latin -american and caribbean IP address registry )
latin american and some caribbean islands
Subnet Mask in Binary (n = network, h = host
nnnnnnnn.hhhhhhhh.hhhhhhhh.hhhhhhhh 11111111.00000000.00000000.00000000 nnnnnnnn.nnnnnnnn.hhhhhhhh.hhhhhhhh 11111111.11111111.00000000.00000000 nnnnnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh 11111111.11111111.11111111.00000000
IPv4 unicast host addresses are in the address range
of 1.1.1.1 to 223.255.255.255. However, within this range are many addresses that are reserved for special purposes.
There is also a Class D multicast block consisting
of 224.0.0.0 to 239.0.0.0
Class E experimental address block consisting
of 240.0.0.0 - 255.0.0.0.
Broadcast packets use resources
on the network and make every receiving host on the network process the packet. Therefore, broadcast traffic should be limited so that it does not adversely affect the performance of the network or devices. Because routers separate broadcast domains, subdividing networks can improve network performance by eliminating excessive broadcast traffic.
A logical AND is
one of three Boolean operations used in Boolean or digital logic. The other two are OR and NOT.The AND operation is used in determining the network address.
Most internal networks, from large enterprises to home networks, use
private IPv4 addresses for addressing all internal devices (intranet) including hosts and routers. However, private addresses are not globally routable.
192.0.3.15
public
209.165.201.30
public
directed broadcast is
sent to all hosts on a specific network. For example, a host on the 172.16.4.0/24 network sends a packet to 172.16.4.255.
multicast clients use
services requested by a client program to subscribe to the multicast group.
Which two situations are the result of excessive broadcast traffic? (Choose two)
slow network operations slow device operations
private addresses
that are used by most organizations to assign IPv4 addresses to internal hosts.
identify the network address of an IPv4 host
the IPv4 address is logically ANDed, bit by bit, with the subnet mask. ANDing between the address and the subnet mask yields the network address.
When an IPv4 host subscribes to a multicast group
the host processes packets addressed to this multicast address, and packets addressed to its uniquely allocated unicast address.
two considerations when planning subnets:
the number of host addresses required for each network and the number of individual subnets needed.
Which two statements are correct about public IPv4 addresses? (Choose two.)
to access a device over the internet, the destination IPv4 address must be a public address public IPv4 address exhausted is a reason why there are private IPv4 address and why organizations are transitioning to IPv6
NAT is used to
translate between private IPv4 and public IPv4 addresses. This is usually done on the router that connects the internal network to the ISP network.
subnet and network are often
used interchangeably. Most networks are a subnet of some larger address block.
Host-A has the IPv4 address and subnet mask: 10.5.4.100 255.255.255.0. Which of the following IPv4 addresses would be on the same network as Host-A? (Choose all that apply)
10.5.4.1 10.5.4.99
Public IPv4 addresses
are addresses which are globally routed between internet service provider (ISP) routers. However, not all available IPv4 addresses can be used on the internet.
IPv4 subnets
are created by using one or more of the host bits as network bits. This is done by extending the subnet mask to borrow some of the bits from the host portion of the address to create additional network bits. The more host bits that are borrowed, the more subnets that can be defined.The more bits that are borrowed to increase the number of subnets reduces the number of hosts per subnet.
Private IPv4 addresses
are not unique and can be used internally within any network.
network address is also referred to
as a prefix or network prefix. Therefore, the prefix length is the number of 1 bits in the subnet mask.
APNIC-Asia Pacific Network Information Center
asia/pacific region
64.104.0.22
public
Multicast transmission
reduces traffic by allowing a host to send a single packet to a selected set of hosts that subscribe to a multicast group
Which devices will not forward an IPv4 broadcast packet by default?
router
Private IPv4 addresses are commonly
used for educational purposes instead of using a public IPv4 address that most likely belongs to an organization
