DOMAIN 1
Defining Network Concepts
Types of Networks
Peer-to-Peer:
Common in home and small office networks.
No central device manages users, files, or folders.
Each device acts as its own server, handling access to its own resources.
Client-Server:
Found in medium to large businesses.
A central server manages user accounts, devices, and permissions.
In Windows-based networks, Active Directory serves as the central management system.
Data Transmission Types
Unicast: Data sent from one device to a single device.
Multicast: Data sent from one device to a specific group of devices.
Broadcast: Data sent from one device to all devices on the network.
IoT Devices
IoT devices can be controlled remotely, often via smartphone apps.
Example: A thermostat that can be programmed remotely through an app.
Cloud and Virtualization Concepts
Hypervisors
A Hypervisor is a tool that manages physical resources for virtual machines. The job of the
hypervisor is to manage how these virtual machines handle physical system resources.
Hyper-V manager is a type II hypervisor, meaning it sits within an operating system, such as
Windows 10 Pro. Hypervisors, such as vSphere and Citrix XenServer are Type I hypervisors,
also known as bare-metal hypervisors. These run on their own operating systems.
Virtual Machines
Within hypervisors, we have virtual machines. Virtual machines are software-based, fully
functional instances of an operating system inside of a hypervisor, allowing us to run multiple
operating systems in one. Two examples of virtual machines are: Linux and Windows. Each
serves a specific purpose. The Linux virtual machine is here so that I do not need a separate
machine on which to run Linux. This instance of Windows is a test machine that I can use to
test things without running tests on my regular operating system. That is another for having a
,virtual: to have a place to test apps and features without risking one’s regular operating
system.
Virtual Switches
There are three types of virtual switches - external, internal, and private.
Private network - allows a virtual machine to communicate only with another virtual machine
on the host.
Internal network - sets up communication between the host system and the virtual machines
on it.
External network - connects virtual machines and the host physical network.
VPN connection
Remote Desktop
RDP is designed for managing a remote desktop, essentially giving you control from a
distance. In contrast, a VPN ensures the security of your connection while also masking your
true location, creating the illusion that you’re connecting from a different server. With a VPN,
users can download data to their personal devices. There’s more responsibility on users to
manage and secure any possible confidential data that they may download.
Doman II
Network Infrastructure
Perimeter Networks
Local area networks (LANs)
- LANs, by definition, are networks that are generally confined to a single building or
even a single area of a building.
- LANs share common resources, such as servers, printers, and to an extent,
workstations.
- One type of LAN is a perimeter network, otherwise known as a DMZ. A perimeter
network holds devices that need to be seen by both the public and private security
zones of a network. These tend to include web servers, email servers, and proxy
servers. In the example we saw earlier, with a firewall on both sides of a perimeter
network, that configuration is known as a back-to-back configuration.
- Here’s another possible configuration for a perimeter network. Notice in this
configuration that there is a single firewall, with connections to all three security
zones. This is known as a three-leg perimeter configuration, with each leg connected
to a single firewall.
, - The difference is that a back-to-back configuration has a firewall on either side of the
perimeter network, while the three-leg perimeter configuration utilizes a single
firewall.
Public—--------------------------------- Firewall—--------------------------- Private
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Perimeter network
Private IP addressing
A private IP address is a range of non-internet facing IP addresses used in an internal
network. Private IP addresses are provided by network devices, such as routers, using
network address translation.
Internet Protocol (IP) addresses identify a device on either the internet or a local
network. IP addresses also enable information to be sent between devices on a
network.
Private IPv4 addresses have the following class configurations:
- Class A IP addresses. Configurations range from 10.0.0.0 to 10.255.255.255.
This class is for large networks and has 8 bits for the network and 24 bits for
hosts.
- Class B IP addresses. Configurations range from 172.16.0.0 to
172.31.255.255. This class is for medium networks and has 16 bits for the
network and 16 bits for the host.
- Class C IP addresses. Configurations range from 192.168.0.0 to
192.168.255.255. This class is for smaller networks and has 24 bits for the
network and 8 bits for the hosts.
Private and public IP addresses:
Private Public
Used for communicating within a private Used to communicate over the public
network. Cannot be directly contacted over internet - outside a private network.
the internet.
, Addresses can be reused per network. Addresses are unique and cannot be reused.
Assigned to a device by a router. Assigned by an ISP.
Has a small set range of possible addresses. Addresses can be any combination of
numbers not within the private IP range.
Reserved Address Ranges
127.0.0.1 is the address for the localhost and is used for testing purposes. It is
specifically known as the loopback address, a special-purpose IP address used by a
host to communicate with itself.
169.254 is a private IP (Internet Protocol) address that the device automatically
assigns itself when it can’t get a valid IP from the router’s DHCP (Dynamic Host
Configuration Protocol) server. The PC will not work because there is not a router to
or from that PC.
VLANs (Virtual LANs)
A virtual local area network (VLAN) is a virtualized connection that connects
multiple devices and network nodes from different LANs into one logical network.
Wired and Wireless LANs
Wired LAN
- Computers and other devices use Ethernet cables to connect to switches.
- The switches connect through Ethernet cables, to one or more routers, which connect
a network to other networks, like the Internet.
Wireless LAN
- Common to homes and small offices, where devices connect to each other through a
wireless access point, often called a wireless router.
- Wireless LANs offer more flexibility than wired LANs in that devices can connect to
the LAN from different places within a building.
Defining Network Concepts
Types of Networks
Peer-to-Peer:
Common in home and small office networks.
No central device manages users, files, or folders.
Each device acts as its own server, handling access to its own resources.
Client-Server:
Found in medium to large businesses.
A central server manages user accounts, devices, and permissions.
In Windows-based networks, Active Directory serves as the central management system.
Data Transmission Types
Unicast: Data sent from one device to a single device.
Multicast: Data sent from one device to a specific group of devices.
Broadcast: Data sent from one device to all devices on the network.
IoT Devices
IoT devices can be controlled remotely, often via smartphone apps.
Example: A thermostat that can be programmed remotely through an app.
Cloud and Virtualization Concepts
Hypervisors
A Hypervisor is a tool that manages physical resources for virtual machines. The job of the
hypervisor is to manage how these virtual machines handle physical system resources.
Hyper-V manager is a type II hypervisor, meaning it sits within an operating system, such as
Windows 10 Pro. Hypervisors, such as vSphere and Citrix XenServer are Type I hypervisors,
also known as bare-metal hypervisors. These run on their own operating systems.
Virtual Machines
Within hypervisors, we have virtual machines. Virtual machines are software-based, fully
functional instances of an operating system inside of a hypervisor, allowing us to run multiple
operating systems in one. Two examples of virtual machines are: Linux and Windows. Each
serves a specific purpose. The Linux virtual machine is here so that I do not need a separate
machine on which to run Linux. This instance of Windows is a test machine that I can use to
test things without running tests on my regular operating system. That is another for having a
,virtual: to have a place to test apps and features without risking one’s regular operating
system.
Virtual Switches
There are three types of virtual switches - external, internal, and private.
Private network - allows a virtual machine to communicate only with another virtual machine
on the host.
Internal network - sets up communication between the host system and the virtual machines
on it.
External network - connects virtual machines and the host physical network.
VPN connection
Remote Desktop
RDP is designed for managing a remote desktop, essentially giving you control from a
distance. In contrast, a VPN ensures the security of your connection while also masking your
true location, creating the illusion that you’re connecting from a different server. With a VPN,
users can download data to their personal devices. There’s more responsibility on users to
manage and secure any possible confidential data that they may download.
Doman II
Network Infrastructure
Perimeter Networks
Local area networks (LANs)
- LANs, by definition, are networks that are generally confined to a single building or
even a single area of a building.
- LANs share common resources, such as servers, printers, and to an extent,
workstations.
- One type of LAN is a perimeter network, otherwise known as a DMZ. A perimeter
network holds devices that need to be seen by both the public and private security
zones of a network. These tend to include web servers, email servers, and proxy
servers. In the example we saw earlier, with a firewall on both sides of a perimeter
network, that configuration is known as a back-to-back configuration.
- Here’s another possible configuration for a perimeter network. Notice in this
configuration that there is a single firewall, with connections to all three security
zones. This is known as a three-leg perimeter configuration, with each leg connected
to a single firewall.
, - The difference is that a back-to-back configuration has a firewall on either side of the
perimeter network, while the three-leg perimeter configuration utilizes a single
firewall.
Public—--------------------------------- Firewall—--------------------------- Private
|
|
|
Perimeter network
Private IP addressing
A private IP address is a range of non-internet facing IP addresses used in an internal
network. Private IP addresses are provided by network devices, such as routers, using
network address translation.
Internet Protocol (IP) addresses identify a device on either the internet or a local
network. IP addresses also enable information to be sent between devices on a
network.
Private IPv4 addresses have the following class configurations:
- Class A IP addresses. Configurations range from 10.0.0.0 to 10.255.255.255.
This class is for large networks and has 8 bits for the network and 24 bits for
hosts.
- Class B IP addresses. Configurations range from 172.16.0.0 to
172.31.255.255. This class is for medium networks and has 16 bits for the
network and 16 bits for the host.
- Class C IP addresses. Configurations range from 192.168.0.0 to
192.168.255.255. This class is for smaller networks and has 24 bits for the
network and 8 bits for the hosts.
Private and public IP addresses:
Private Public
Used for communicating within a private Used to communicate over the public
network. Cannot be directly contacted over internet - outside a private network.
the internet.
, Addresses can be reused per network. Addresses are unique and cannot be reused.
Assigned to a device by a router. Assigned by an ISP.
Has a small set range of possible addresses. Addresses can be any combination of
numbers not within the private IP range.
Reserved Address Ranges
127.0.0.1 is the address for the localhost and is used for testing purposes. It is
specifically known as the loopback address, a special-purpose IP address used by a
host to communicate with itself.
169.254 is a private IP (Internet Protocol) address that the device automatically
assigns itself when it can’t get a valid IP from the router’s DHCP (Dynamic Host
Configuration Protocol) server. The PC will not work because there is not a router to
or from that PC.
VLANs (Virtual LANs)
A virtual local area network (VLAN) is a virtualized connection that connects
multiple devices and network nodes from different LANs into one logical network.
Wired and Wireless LANs
Wired LAN
- Computers and other devices use Ethernet cables to connect to switches.
- The switches connect through Ethernet cables, to one or more routers, which connect
a network to other networks, like the Internet.
Wireless LAN
- Common to homes and small offices, where devices connect to each other through a
wireless access point, often called a wireless router.
- Wireless LANs offer more flexibility than wired LANs in that devices can connect to
the LAN from different places within a building.
