MTA 98-366 Udemy Cert Study Cards Flashcards
(173 cards)
1
Q
Client-Server Network?
A
- Network is Composed of Clients and Servers
- Servers Provide Resources
- Clients Receive Resources
- Servers Provided Centralized Control Over Network Resources (files, printers, authentication, etc.)
2
Q
Peer-to-Peer Network?
A
- All Computers on the Network Are Peers
- No Dedicated Servers
- There Is No Centralized Control over Shared Resources
- Any Individual Machine Can Share Its Resources as It Pleases
- All Computers on the Network Can Act as Either a Client (Receive Resources) or a Server (Provide Resources)
3
Q
LAN?
A
Local Area Network
A Computer Network with a Small Geographical Area, such as a Single Room, Building or Group of Buildings.
4
Q
CAN?
A
Campus Area Network
A Computer Network of Multiple Interconnected LANs in a Limited Geographical Area, such as a Corporation, Government Agency, or University Campus.
5
Q
MAN?
A
Metropolitan Area Network
A Computer Network that Interconnects Users with Computer Resources in a City.
Larger than a Campus Area Network, but Smaller than a Wide Area Network.
6
Q
WAN?
A
Wide Area Network
A Computer Network that extends over a large geographical distance, typically multiple Cities and Countries.
7
Q
MAC Address?
A
- Physical Address of the Network Adapter Card
- OSI Layer 2 (Data Link) Layer Address
- TCP/IP Layer 1 (Network Interface) Layer Address
- 6 Bytes (48 bits), Usually Represented Hexadecimal
8
Q
Duplex Communication?
A
Network Communication will occur in either full or half duplex mode.
Half Duplex - Can send and Receive Data, but not at the same time.
Full Duplex - Can send and Receive Data simultaneously.
9
Q
Physical & Logical Network Topologies?
A
Physical - Define the Physical Design of a Network, including the Network Devices, Locations, and Cables. Similar to a Building Blueprint.
Logical - Define how data moves throughout a Network (CSMA/CA, CSMA/CD, Ethernet.
10
Q
Bus Topology?
A
All devices are connected to a single network Cable.
Terminators are required for both ends of the cable.
A single break in the cable will take down the entire network.
11
Q
Ring Topology?
A
All devices are connected in a circular fashion.
Each computer is connected to two other computers.
Data travels from node to node with each computer handling data, either unidirectional or bidirectional.
12
Q
Star Topology?
A
All devices are connected to a Central Device. (Usually a Switch or a Hub)
Popular topology in today’s networks.
Used in most large and small networks.
Central device is a single Point of Failure.
13
Q
Mesh Topology?
A
Each device is connected to every other device by separate cabling.
Highly redundant and fault-tolerance.
Used in WANs.
Expensive to Install.
14
Q
Types of Network Cabling?
A
Coaxial
Twisted Pair
Fiber Optic
15
Q
Ethernet?
A
- Is a Network Protocol that controls how data is transmitted over a LAN.
- Referred to as the Institute of Electrical and Electronics Engineers (IEEE) 802.3 Standard.
- It supports networks built with thin and thick coaxial, twisted-pair, and fiber optic cabling.
- The original Ethernet Standard supported 10Mbps Speeds, but the latest supports much faster speeds.
- Ethernet uses CSMA/CD access methodology.
16
Q
Ethernet xxBaseT Naming details?
A
Ethernet uses a “xx Base T” naming convention.
• xx: Speed of the Cable.
• Base: Baseband communication (Single Frequency)
• T: Type of Cable.
17
Q
Ethernet xxBaseT Naming? (From Twisted Pair to Fiber)
A
10BaseT - 10Mbps Twisted-Pair Standard Ethernet
10BaseF - 10Mbps Fiber Optic Standard Ethernet
100BaseT - 100Mbps Twisted-Pair Fast Ethernet
100BaseF - 100Mbps Fiber Optic Fast Ethernet
1000BaseT - 1Gbps Twisted-Pair Gigabit Ethernet
1000BaseF - 1Gbps Fiber Optic Gigabit Ethernet
18
Q
Twisted-Pair Copper Cabling?
Why are they Twisted?
Security Concerns?
A
4 Twisted Pairs of Wires with a RJ-45 Connector.
Balanced Pair operation
• + & - Signals
• Equal & Opposite Signal
To help reduce Interference, Crosstalk, Noise.
Security Concerns consist of Signal Emanations
100 Meters Max Distance, Signal Attenuation.
19
Q
Shielded VS Unshielded Twisted Pair?
A
UTP - Unshielded Twisted-Pair = More susceptible to electromagnetic interference EMI.
STP - Shielded Twisted-Pair = Less susceptible to EMI and Crosstalk (if each pair is shielded).
EMI - Electromagnetic Interference = The disruption of the operation of an electronic device when it’s in the vicinity of an electromagnetic field caused by another electronic device. (Manufacturing Equipment, Microwave Ovens, etc.)
20
Q
Twisted-Pair Copper Cabling Categories?
A
Category 3 - CAT3 = 10Mbps Category 5 - CAT5 = 100Mbps Category 5e - CAT5e = 1Gbps Category 6 - CAT6 = 1Gbps & 10Gbps for Shorter Runs Category 6a - CAT6a = 10Gbps
21
Q
Plenum-Rated Cable?
A
Plenum-Rated cables have a special insulation (Teflon Coated) that has low smoke, low flame, and non-toxic characteristics.
If they catch fire, they won’t release toxic fumes.
22
Q
Twisted-Pair Wiring Standards - 2 Standards?
A
568A & 568B
568B is Newer and the Recommended Standard.
Either can be used.
Standards are Important to Lower Costs, Increase Interoperability, and Easier Maintenance.
23
Q
Straight-Through Cable?
A
Connecting “UNLIKE” Devices
• Computer to Switch
• Switch to Router
24
Q
Crossover Cable?
A
Connecting “LIKE” Devices.
• Router to Router
• Computer to Computer
25
Fiber Optic Cabling?
Glass or Plastic Fiber that Carries Light.
• High Bandwidth
• Long Distances
• Immune to Electromagnetic Interference (EMI)
• Doesn't Emanate SIgnals
Two Types:
• Multi-Mode Fiber (MMF) - Shorter Distances (LAN)/Building to Building up to 1 Miles.
• Single-Mode Fiber (SMF) - More expensive, Longer Distances WAN/Across Town, up to 25 Miles.
26
Fiber Optic Cable Characteristics?
Single-Mode -- 10Gbps -- 25 Miles -- Glass Core
Multi-Mode -- 10Gbps -- 300 Meters -- Plastic Core
Multi-Mode -- 1Gbps -- 500 Meters -- Plastic Core
Multi-Mode -- 100Mbps -- 1 Mile -- Plastic Core
27
The OSI Model?
Breaks down the Complex Task of Computer-To-Computer Network Communication into 7 Layers.
Upper Layers = Host Layers
• Handled by the Host Computer and Performs Application-Specific Functions, such as Data Formatting, Encryption, and Connection Management.
Lower Layers = Media Layers
• Provide Network-Specific functions, such as routing, addressing, and flow control.
28
The OSI Model?
7 - Application Layer -- DATA - Host Layer ------------ ALL
6 - Presentation Layer -- DATA - Host Layer ---------- PEOPLE
5 - Session Layer -- DATA - Host Layer ----------------- SEEM
4 - Transport Layer -- Segment - Media Layer ------- TO
3 - Network Layer -- Packet - Media Layer ------------ NEED
2 - Data Link Layer -- Frame - Media Layer ----------- DATA
1 - Physical Layer -- Bit - Media Layer ------------------- PROTECTION
29
OSI Layer 1?
Physical Layer - Defines the Physical and Electrical Medium for Network Communication.
• Send Bits and Receives Bits (1's and 0's)
• Network Cabling, Jacks, Patch Panels, etc...
• Encoding Signal Types
• Ethernet IEEE 802.3 Standard
30
OSI Layer 2?
Data Link Layer - Provides Physical Transmission of the Data.
• Ensures that Messages are Delivered to the Proper device on a LAN using Hardware Addresses (MAC Address)
• Translates Messages from the Network Layer into Bits for the Physical Layer.
• The "Switching" Layer.
31
OSI Layer 3?
Network Layer - AKA, the Routing Layer - Provides logical addressing and routing services.
• Places Two Addresses in the Packet
- Source Address & Destination Address
• Internet Protocol (IP)
- The Primary Network Protocol used on the Internet, IPV4 and IPv6 Logical Addresses.
32
OSI Layer 4?
Transport Layer - Ensures data is delivered error-free and in sequence.
• Segments data and reassembles correctly.
• Can be connection-oriented (TCP) or connection-less (UDP).
• Considered the "Post Office" Layer
- TCP (Transmission Control Protocol)
- UDP (User Datagram Protocol)
33
OSI Layer 5?
Session Layer - Responsible for setting up, managing, and then tearing down sessions between network devices.
• Ensures data from different application sessions are kept separate.
• Coordinates communication between systems - Start, Stop, Restart.
34
OSI Layer 6?
Presentation Layer - Ensures that data transferred from one system's Application Layer can be read by the Application Layer on another one.
• Provides Character code conversion, data compression, and data encryption.
• Example - HTML Converted to ASCII Format.
35
OSI Layer 7?
Application Layer - Where users communicate to the Computer
• Acts as an Interface between an application and end-user protocols.
• Provides an interface to communicate with the network (Outlook, Chrome, etc...)
• Applications doesn't reside in the Application Layer protocol, but instead interfaces with Application-Layer Protocol.
36
The TCP/IP Model?
* The CTP/IP Suite is the Most Common used Protocol Suite in the Networking World.
* It is essentially the protocol suite in which the Internet was built.
* It is the Standard for Computer Networking
* It is based on a 4 Layer Model, that is similar to the OSI Model.
37
TCP/IP Model?
• Transmission Control Protocol/Internet Protocol
• Common called the Internet Protocol Suite because it was designed for the Internet, but LANs use it too.
• First Two Protocols Defined in the Suite Were --- TCP and IP, hence TCP/IP.
• Similar to the OSI Model, but Simpler:
- OSI is Conceptual
- TCP/IP was Actually Implemented
38
TCP/IP 4 Layers?
Application -- FTP, TFTP, DNS, HTTP(S), TLS/SSL, SSH, POP3, IMAP4, NTP, Telnet, SMTP, SNMP
Transport -- TCP, UDP, and Ports
Internet -- IP Addressing (Routing), ICMP, ARP
Network Interface -- Ethernet, Token Ring
39
Internet Control Messaging Protocol?
ICMP = Provides Error Checking and Reporting Functionality
• Sends management messages between systems
- Echo Request, Echo Reply
- Destination Unreachable
• Great tool for troubleshooting network - PING Command
• Command: ping google.com
40
Address Resolution Protocol?
ARP = Resolves IP Addresses to MAC Addresses
• Finds the Hardware Address of a Host from a Known IP Address and visa versa (RARP).
• Command: arp -a
41
Transmission Control Protocol?
TCP = Connection-Oriented, 3 Way Handshake
• SYN > SYN/ACK > ACK
• Reliable Delivery of Data in Correct Order
• Virtual Connection Between 2 Devices.
• Assures delivery of packets through error-checking (Data Sequencing).
42
User Datagram Protocol?
UDP = Scaled-Down, Economic version of TCP
• Connectionless and Unreliable
• No Data Retransmissions
• "Best Effort"
• Used a lot for Streaming Real-Time data, VOIP, Video Streams, Audio Streams, etc..
43
TCP/UDP Ports?
* Computers require Ports because of Network Application Multitasking.
* Ports allow you to associate packets with TCP/IP Protocols.
* Network Services are assigned a Port Number - DNS, HTTP, FTP, POP3, Telnet, Etc. etc.
44
Types of Ports and Basic Port Info?
Approximately 65,536 Ports Available.
Well Known Ports -- 0 to 1023 -- Assigned to Well Known Protocols
Registered Ports -- 1024 to 49,151 -- Registered to Specific Protocols
Dynamic Ports -- 49,152 to 56,535 -- Not Registered and Used for any Purposes.
45
FTP Port?
File Transfer Protocol -- 20, 21 -- TCP
46
SSH Port?
Secure Shell Protocol -- 22 -- TCP
47
Telnet Port?
23 -- TCP
48
SMTP Port?
Simple Mail Transfer Protocol -- 25 -- TCP
49
DNS Port?
Domain Name System -- 53 -- UDP
50
DHCP Port?
Dynamic Host Configuration Protocol -- 67, 68 -- UDP
51
TFTP Port?
Trivial File Transfer Protocol -- 69 -- UDP
52
HTTP Port?
Hypertext Transfer Protocol -- 80 -- TCP
53
Kerberos Port?
88 -- UDP
54
POP3 Port?
Post Office Protocol v3 -- 110 -- TCP
55
NTP Port?
Network Time Protocol -- 123 -- UDP
56
IMAP4 Port?
Internet Message Access Protocol v4 -- 143 -- TCP
57
SNMP Port?
Simple Network Management Protocol -- 161 -- UDP
58
LDAP Port?
Lightweight Directory Access Protocol -- 389 -- TCP
59
SSL Port?
Secure Socket Layer -- 443 -- TCP
60
HTTPS Port?
Hypertext Transfer Protocol Secure -- 443 -- TCP
61
IPSec Port?
Internet Protocol Security -- 500 -- UDP
62
L2TP Port?
Layer 2 Tunneling Protocol -- 1701 -- UDP
63
PPTP Port?
Point to Point Tunneling Protocol -- 1723 -- TCP
64
RDP Port?
Remote Desktop Protocol (RDS - Remote Desktop Service) -- 3389 -- TCP
65
Ports in Action?
Communication originates from your computer utilizing a high random port to communicate across a LAN/WAN/Internet to communicate with a Remote Server.
The Web Server will be listening in on a Specific Port for it's associated TCP/IP Protocols.
66
Browser Application Protocols?
HTTP - Hypertext Transfer Protocol
• TCP
• Provides for browsing services for the WWW (World Wide Web)
HTTPS - Hypertext Transfer Protocol SECURE
• TCP
• Provides access to resources on the Internet in a secure fashion.
• Encryption via TLS/SSL
TLS/SSL - Transport Layer Security & Secure Socket Layer
• TCP
• Cryptographic protocols for enabling secure online data-transfer activities
• TLS has replaced SSL
67
File Transfer Application Protocols?
FTP - File Transfer Protocol
• TCP
• Transfers files between systems
• Authentications with a username and password
• Full-Featured functionality (List, Add, Delete, Etc.)
TFTP - Trivial File Transfer Protocol
• UDP
• Very simple file transfer application
• Can send and receive files; no directory browsing
• No Authentication
68
Mail Application Protocols?
```
SMTP - Simple Mail Transfer Protocol
• TCP
• Used most often for SENDING Mail.
• Transferring between mail servers.
POP3 - Post Office Protocol v3
• TCP
• Receive Email
• Designed for intermittent connectivity
IMAP4 - Internet Message Access Protocol v4
• TCP
• Another mail Client Protocol
• Allows users to access email on servers and either read the email on the server or download the email to the client machine.
```
69
Management Protocols?
DNS - Domain Name Services
• Converts domain names to IP Addresses
• Google.com = 74.125.224.52
• NSLookup Command
NTP - Network Time Protocol
• Automatically synchronized clocks on network devices.
SNMP - Simple Network Management Protocol
• SNMPv1, SNMPv2, SNMPv3
• Collects and manipulates network information
• Used for Network management and maintenance.
• v1 - The Original, Clear Text Data
• v3 - Encrypted Data
70
Remote Communication Protocols?
Telnet - Telecommunication Network
• TCP
• Provides a Virtual Terminal Protocol logging into and managing devices remotely.
• Not used often anymore because unencrypted communication.
SSH - Secure Shell
• TCP
• Looks and Acts like Telnet, but communication is encrypted!!
• PuTTY SSH Client Popular
71
Unicast Communication?
One to One Communication
| One Source to One Destination
72
Multicast Communication?
One to Many Communication to those whom Desire.
| Multicast Groups
73
Broadcast Communication?
One to ALL Communication
| All nodes on the Network
74
Network Access Methods: CSMA & Token Ring?
CSMA
• Carrier Sense - Checks Networks for Communication
• Multiple Access - Multiple devices using network.
• Collision Detection - Wired Network
• Collision Avoidance - Wireless Network
Token Ring
• The Token
Passed between devices on the Network.
Only device with token can send data.
Token prevents network collisions.
75
IP Addressing?
An IP Address is a logical address used in order to uniquely identify a device on an IP network.
It's a Network Layer Address, and there are 2 Types.
• IPv4
• IPv6
76
IPv4 Addressing?
Made up of 32 Binary Bits, which can be divided into a Network Portion and a Host Portion with the help of a Subnet Mask.
• 32 Binary bits are broken into 4 Octets (1 octet = 8 bits)
• Each octet is converted to decimal and separated by a period.
192 . 168 . 1 . 131
11000000 . 10101000 . 00000001 . 100000011
77
IPv4 Host and Network Address?
An IP Address is broken down into two parts
• Network Address
• Host Address
• Network Address + Host Address = IP Address
78
IPv4 Addressing -- IP Address, Subnet Mask, and Default Gateway?
Each device on a Network is assigned an IP Address, a Subnet Mask, and a Default Gateway.
• IP Address - Unique logical address assigned to each device on a network.
• Subnet Mask - Used by the device to determine what subnet it's on.
• The Router's IP Address, that allows the Device to communicate outside it's local subnet.
79
IPv4 Address Classes with Network/Host?
CLASS ----- Network Bits ------- Host Bits ------------- Address Range
A 8 24 1.0.0.0 - 127.255.255.255 ------- Network.Host.Host.Host
B 16 16 128.0.0.0 - 191.255.255.255 --- Network.Network.Host.Host
C 24 8 192.0.0.0 - 233.255.255.255 -- Network.Network.Network.Host
80
IPv4 Addresses with Subnet Masks?
Class A -- Network.Host.Host.Host -- 10.0.0.15 -- (255.0.0.0) -- (11111111.00000000.00000000.000000000)
Class B -- Network.Network.Host.Host -- 172.16.0.110 -- (255.255.0.0) -- (11111111.11111111.00000000.00000000)
Class C -- Network.Network.Network.Host -- 192.168.1.50 -- (255.255.255.0) -- (11111111.11111111.11111111.00000000)
81
IPv4 CIDR Notation?
"Slash" Notation tells you how many bits are associated with the Subnet Mask.
```
/8 = 11111111.00000000.00000000.00000000 = 255.0.0.0
/16 = 1111111.11111111.00000000.00000000 = 255.255.0.0.
/24 = 11111111.11111111.11111111.00000000 = 255.255.255.0
/32 = 11111111.11111111.11111111.11111111 = 255.255.255.255
```
82
The Reason for Subnetting IPv4 Addresses?
Using default Class A, B, and C Subnets (Called Classful IP Addressing) is inefficient.
• Wastes unused IP Addresses (Public IP Addresses)
• Allows you to create multiple logical networks that exist within a single Class A, B, or C Network.
• Breaks a major network down into multiple smaller subnetworks (Subnets)
• Allows for more efficient routing via router summarization.
83
Process of Subnetting?
We borrow Host Bits to create more Sub-Networks (Subnets) from a Class A, B, or C Network.
When you borrow host bits:
• You create additional subnetworks
• You also decrease the amount of host IP addresses available to use.
84
Disadvantages of IPv4?
• Not enough IP addresses (Approximately 4.3 billion addresses)
World Population (2018) +7.6 Billion
Multiple Network devices per user (Computers, Smart Phones, Tablets, Etc...)
• Cluttered Internet Routing Tables
• Security is Optional
Encrypted Data is Optional
85
IPv6 Solutions to IPv4 Problems?
• Plethora of Addresses
340, 282, 366, 920, 938, 463, 374, 607, 431, 768, 211, 456
Approximately 792,000x as many IPv4 Addresses
Approximately 448,000x the Current World Population
• Simplified Internet Routing Tables
Packet Header enables more efficient routing.
Fixed at 40 bytes verses IPv4 variable length, packet header for optional fields.
IPv4 has 14 Header Fields verses 8 for IPv6 --- Smaller and More Efficient.
• Easier and Automated Configuration compared to IPv4.
Stateless Auto-Config
Hosts can assign their own IP addressing using it's MAC Address and the server's host address.
No need for a DHCP Server.
• Security is Required
Internet Protocol Security (IPSec) is Required
Source IP can be Authenticated
Data in transit is encrypted.
86
IPv4 vs IPv6 Info?
IPv4 ---------------------------------- IPv6
Deployed? 1981 ---------------------------------- 1999
Address Size? 32 Bit ------------------------------- 128 Bit
# of Addresses? 4.294mil --------------------------- ALOT
Addressing? Class (A,B,C) Based ----------- Classless
87
Reasons IPv4 is still used?
* Subnetting / CIDR
* Network Address Translation (NAT)
* Use of Private IP Addresses
* DHCP
88
IPv6 Addressing?
• Displayed in 8, 16 Bit Hexdecimal Blocks called Hextets.
Example: 2001:0DB8:85A3:0000:0000:8A2E:0370:7334
• Colon Separator between blocks/hextets.
• We can simplify by suppressing leading 0's.
• Can also compress contigious blocks of 0's into "::" once per address.
Example: 2001:DB8:85A3::8A2E:370:7334
89
Types of IPv6 Addresses?
```
Unicast (One to One)
• Global Address
Similar to Public IPv4 Addresses
Routable IP Addresses.
• Link-Local Addresses
Similar to APIPA Addresses
FE80 Prefix
• Unique Local Addresses
Similar to Private IPv4 Addresses
FC or FD Prefix
```
Multicast (One to Man)
• Broadcast Replaced by expanded use of Multicast
Anycast (One to One of Many)
• Identifies multiple interfaces, but packet of data is delivered to the nearest network interfaces (Routing Distance)
Loopback Address
• ::1
90
IPv4 to IPv6 Transition?
• IPv6 not natively backwards compatible with IPv4.
• To aid in transition, as well as co-existence of IPv4 and IPv6, there are 3 transition technologies you need to know.
1.) Dual IP Stack
2.) IPv4 Mapped Addresses
3.) Tunneling
91
Dual Stack IP?
* When both IPv4 and IPv6 protocols exist within an Operating System.
* Can be used independently or together.
92
IPv4 Mapped Addresses?
* Dual IP Stack can map IPv4 addresses to IPv6 Addresses.
* First 80 Bits are 0, next 16 are 1 (Shown as FFFF) and last 32 bits are populated with IPv4 Addresses.
* Example: ::ffff:192.168.1.100
93
IPv4 to IPv6 Tunneling?
* IPv6 Packets are encapsulated inside IPv4 datagram.
* Microsoft utilizes the Teredo Virtual adapter to accomplish this.
* You can use ipconfig /all in command prompt to see if your system is using Teredo.
94
Hubs?
• Used to connect devices together within a network.
• Used in Early Networks; replaced by Switches.
• "Multi-Port Repeater"
Traffic goes in one port and is repeated out every other port.
OSI Layer 1 Device
Dumb Network Device
• Much less efficient than a switch.
• You may encounter Hubs in older network environments.
95
Switch?
• Connects Devices together just like a Hub.
• Intelligent Network Device
• Memorizes the MAC Address of Each Device connected to it via a MAC Address Table.
• Pays attention to SOurce and Destination MAC Addresses during communication process.
• Breaks up Collision Domains
Traffic goes in one port and is repeated out to only destination port.
Designed for HIgh Bandwidth
Standard in today's network infrastructure.
96
Hub vs Switch?
Hub ------------------------------------------ Switch
Dumb Device --------------------------- Intelligent Device
Floods all Ports ------------------------- Learns Ports by MAC Address, only sends to Specified Port.
OSI Layer 1 ------------------------------- OSI Layer 2
Inefficient --------------------------------- Efficient
Decreased Throughput ------------- Increased Throughput
Collisions More Frequent ---------- Collisions Less Frequent
Less Secure ----------------------------- More Secure
97
Collision Domains?
• A Group of Network devices on the same network segment where there is a potential for data to collide with one another.
Hubs
• Broadcast Traffic (One to All)
• One Large Collision Domain
• Half-Duplex Communication
Switch
• Unicast Traffic (One to One)
• Multiple Collision Domains
• Full-Duplex Communication
98
CSMA/CD?
Carrier Sense Multiple Access/Collision Detection
• Typically used with Hubs (Half Duplex Communication) where there is one large Collision domain.
• Can be used with Switches if a half-duplex device is connected to it, such as a hub.
Helps hosts decide when to send packets on a shared network segment and to detect collisions.
99
CSMA/CD Process?
1. Hosts check for the presence of a digital signal on the wire.
2. If a digital signal isn't detected, the host will begin sending a frame of data.
3. If another host beings transmitting and a collision occur, the transmitting host will send a jam signal that causes all hosts on the network segment to stop sending data.
4. After a random period of time, hosts re-transmit their packets.
100
Layer 3 Switches?
Provide Layer 2 Switching and Layer 3 Routing.
• OSI Layer 2 (Data Link): Switching via MAC Address
• OSI Layer 3 (Network): Routing via IP Addresses
Managed Switch Capability
Used in Conjunction with VLANs
One Device instead of Router and Switch.
101
Virtual LANs?
VLANs (Virtual Local Area Networks)
Essential LANs within a LAN
Break up a Large "Physical" LAN into several smaller "Logical" LANs.
Accomplished with Managed Switches.
Assign specific Switch interfaces (Ports) to specific VLANs.
• Human Resource VLAN (Interfaces 1, 2, 3)
• Accounting VLAN (Interfaces 4, 5, 6)
102
Benefits of VLANs?
* Reduces Broadcast Domains
* Segments Network by Role
* Increases Security
* Devices cannot communicate with other VLANs
* Group Devices by NEED, not Physical Location.
103
Unmanaged Switches?
* Completely Unmanaged
| * Unbox It, Plug it in, and it works without any administration.
104
Managed Switches?
Can be configured and managed by Network Admins typically via Telnet or SSH.
* Configure static entries in the MAC Table
* Configure half or full duplex on specific ports.
* Monitor switch performance with SNMP.
* Create VLANs
* Configure Port Mirroring
Much more expensive than unmanaged Switches.
105
Switch Speed Standards?
IEEE 802.3 (Ethernet) ---- 10 Mbps ---- E0, E1, Etc...
IEEE 802.3u (Fast Ethernet) ---- 100 Mbps ---- F0, F1, Etc.
IEEE 802.3z (Gigabit Ethernet) ---- 1000 Mbps (1Gbps) ---- Gi0, Gi1, Etc..
IEEE 802.3an (Gigabit Ethernet) --- 10Gbps ---- Gi0, Gi1, Etc..
106
Transmission Speeds?
Many Switches can "Auto Sense" to detect the transmission speed capabilities of connected devices.
* 10/100: Autosensing switch capable of 10Mbps or 100Mbps speed.
* 100/1000: Autosensing switch capable of 100Mbps or 1Gbps speed.
* 1000/10000: Autosensing switch capable of 1Gbps or 10Gbps speed.
* 10/100/1000/10000: Autosensing switch capable of 10Mbps, 100Mbps, 1Gbps or 10Gbps speed.
107
Switch Uplink Port?
* The Switch uplink port is a special port used to connect a Switch to another Switch or Router.
* Usually used to connect to the next "higher" device in the network topology, IE Smaller LAN to Larger Network in a building or campus setting.
* You can bundle uplink ports to increase your uplink speed using the link aggregation control protocol. (LACP)
108
Router?
* Used to Connect Different Networks TOgether
* Routes Traffic Between Networks using IP Addresses
* Uses Intelligent Decisions (Routing Protocols) to find the best way to get a packet of information from one network to another.
* OSI Layer 3 Device
Layer 3 = Router
Layer 2 = Switch
Layer 1 = Hub
109
Static VS Dynamic Routing?
Static Routing
• Manual Process
• You manually tell your router where to route traffic
• Often seen as the "Default" route on the Internet.
Dynamic Routing
• Automatic, and Hands Off
• Routers are able to make changes to the route on the fly
• All routing decisions are handled by the protocol
• RIP, RIPv2, OSPF
110
The Next Hop?
The Next Hop is crucial piece of information.
* It's why the Router Exists
* The Router Sends / Forwards packets to the "Next Hop", IE: The Next Router
* This process continues until the packet reaches it's destination network or the Packet is dropped.
111
Link State Routing Protocol: OSPF?
• Open Shortest Path First (OSPF)
• Information Passed between Routers is related to the current connectivity.
If the link is UP, then the packet can go there.
If the link is DOWN, the packet can't go there.
• Requires all Routers to know about the paths reachable by all other Routers on the Network.
Where it is, how fast it is, etc...
• Uses "Cost" Metrics to determine "best" route by including link state and speed.
112
Distance Vector Routing Protocol: RIP?
• Router information Protocol (RIP) and (RIPv2).
• Find the best path to a remote network by judging distance.
How many "hops" away is another network?
• Distance = Hops
Each time a packet goes through a router, it equals a "Hop".
15 "Hops" maximum distance.
• Vector = Which Direction
The vector with the fewest hops is the best route.
113
RIP vs RIPv2?
RIP ------------------------------------------------------------RIPv2
Max Hops = 15 ------------------------------------------- Max Hops = 15
Doesn't Support Authentication ------------------ Supports Authentication
Uses Broadcast Communication ------------------ Uses Multicast Communication.
114
Network Address Translation?
NAT
• Translates Private IP Addresses to Public IP Addresses, allowing us to Map Multiple Private IP Addresses to a single Public IP address.
115
DHCP?
Dynamic Host Configuration Protocol
• Automatically Assigns IP Addresses to Hosts
• Makes Administering a Network Much Easier
• The Alternate is Static IP Addressing
116
DHCP IP Addressing Leasing Process?
1. Client Requests an IP Address by broadcasting a "DHCP Discover" Message on it's Local Subnet.
2. When the DHCP Server receives the request, it'll respond with a "DHCP Offer" message containing an IP Address and lease the information.
3. If no DHCP Server is Available, the client will use Automatic Private IP Addressing (APIPA) alternate configuration, if it's configured.
4. The Client then accepts the "DHCP Offer" by replying with a "DHCP Request" message to the DHCP Server.
5. The DHCP Server assigns the client the address and sends a "DHCP Ack" (Acknowledgement) message in response, finalizing the DHCP IP Address Lease.
117
DNS Hierarchy?
Root DNS Servers
Top Level Domain DNS Servers = .com, .mil, .edu, .net, .org
Second Level Domain DNS Servers = EX: Microsoft.com
Third Level Domain DNS Servers = EX: Technet.Microsoft.com
118
Common DNS Records?
A (Host) - Resolves a domain name to an IPv4 Address
AAA (Host) - Resolves a domain name to an IPv6 Address
PTR (Pointer) - Resolves an IP Address to a domain name
CNAME (Alias) - Resolves one domain name to another domain name, which allows multiple domain names to be resolved to the same IP Address.
MX - Used for mail exchange server (Email Servers)
SRV - Required by Active Directory (AD) to locate servers running specific services.
NS - Identifies DNS Name Servers.
119
Name Resolution Process?
1. Host Cache/Hosts File
2. DNS Server
3. NetBIOS Cache
4. WINS Server
5. Broadcast
6. LMHosts File
120
NetBIOS Names?
• Network Basic Input/Output System (NetBIOS)
• 16 Characters in Length with 15 Characters used for the name and the 16th represents the NetBIOS Servers.
• EXAMPLES:
WebServer1 <20>
PrimaryFileServ <20>
• Used in conjunction with a WINS Server and LMHosts file.
• Not used as part of an Active Directory Domain.
121
Host Names?
• Fully Qualified Domain Name (FQDN)
• Can be up to 255 Characters in Length and part of an Active Directory Domain
• EXAMPLE:
WebServer1.Alnet.Internal
DNS.Alnet.com
• The primary type of name used on networks today.
122
Name Resolution Step 1: Host Cache/Hosts File?
Your computer checks DNS query responses in DNS Cache and it always checks there first.
We can view a computer's DNS cache with the following command:
• ipconfig /displaydns
Windows has a "Hosts" fifle where you can manually map domain names / host names to an IP Address.
• Any entry in the "Hosts" file is added to the DNS cache.
• C:\Winddows\System32\drivers\etc
123
Name Resolution Step 2: DNS Server?
If your computer cannot find the domain name / host name in its Host Cache, it will query its configured DNS server in it's TCP/IP Settings.
124
Name Resolution Step 3: NetBIOS Cache?
• NetBIOS names resolved by WINS Server names are placed in a NetBIOS Cache.
• We can use following command to view a computer's NetBIOS cache:
nbstat -c
125
Name Resolution Step 4: WINS Server?
If a NetBIOS name isn't in the computer's NetBIOS cache, the computer will then query the WINS Server.
126
Name Resolution Step 5: Broadcast?
If WINS doesn't resolve a NetBIOS name, the computer will attempt to resolve the name using a network broadcast over its local subnet.
127
Name Resolution Step 6: LMHosts File?
• The last step is to look up the NetBIOS name in the LMHosts file if all other steps have failed to resolve the name's IP address.
• However, newer Windows OSs don't include a working LMHosts file:
Windows 7 and Newer
Windows Server 2008 and Newer
You have to manually create an LMHosts file on these systems.
C:\Windows\System32\drivers\etc
128
Wireless Networking?
* IEEE 802.11 - Standard for Wireless Networking
* Wireless LANs (WLAN) use radio frequencies (RFs) that are radiated into e air from an antenna that creates radio waves.
* Can extend the connection of a wired network, used to connect entire local area networks together.
129
Wireless Repeater VS Wireless Bridge?
Wireless Repeater
• Used to extend the coverage of a wireless network
• Placed at points where wireless signal is degrading to extend the wireless coverage.
Wireless Bridge
• Similar to a wireless repeater, but can also connect different 802.11 standards (a, b, g, n, etc.) together in what is known as "Bridge Mode".
130
Wireless Network Modes?
Infrastructure
• Most wireless networks are deployed in infrastructure mode.
• When wireless devices connect to and are authenticated by a Wireless Access Point (WAP)
Ad-Hoc (Peer-To-Peer)
• When wireless devices communicate directly with one another - no wireless access point is used.
131
Service Set Identifier (SSID)?
* All wireless networks have an Service Set Identifier (SSID) in Infrastructure Mode.
* The SSID is the wireless networks name.
* Wireless access points broadcast a wireless network's SSID so it is viewable by devices with a wireless network adapter.
* For Network Security Reasons, SSID broadcasting can be disabled/hidden.
132
Wireless Network CSMA/CA?
• While Wired Ethernet Networks use CSMA/CD, wireless Ethernet networks use CSMA/CA, where the CA stands for "Collision Avoidance".
• Wireless networks cannot detect collisions, so they use CA to avoid network collisions.
Before transmitting, a device will listen to see if anyone else is transmitting data.
If no other devices are transmitting, it will transmit.
If it hears data transmissions, it will wait and then recheck.
133
Wireless 802.11 Standards?
802. 11 ------------- 2Mbps ------------- 2.4GHz
802. 11a ----------- 54Mbps ------------ 5GHz
802. 11b ----------- 11Mbps ------------- 2.4GHz
802. 11g ----------- 54Mbps ------------ 2.4GHz
802. 11n ----------- 600Mbps ---------- 2.4GHz & 5GHz
802. 11ac ---------- 866.7Mbps ------- 5GHz
134
Wireless Network Security Standards?
• The Availability Security Protocols are:
- WEP: Wired Equivalent Privacy
Considered Compromised
- WPA: Wi-Fi Protected Access
Considered Compromised
- WPA2: Wi-Fi Protected Access v2
Current Standard
- 802.1x: Enterprise Mode
Provides Wireless Authentication
135
Wired Equivalent Privacy (WEP)?
* The Original security protocol used to secure wireless networks.
* Has significant vulnerabilities (Weak encryption and key management) and software is easily attainable to crack WEP-protected networks in minutes.
136
W-Fi Protected Access (WPA)?
* WPA was created as an interim replacement for WEP. after vulnerabilities became widely known and exploited.
* Was never designed to be a long-term solution, just an interim solution until WPA2 became available.
* It was cracked in NOV 2008.
137
Wi-Fi Protected Access v2 (WPA2)?
* WPA2 is the permanent replacement for WEP and WPA
* WPA2 used Advanced Encryption Standard (AES) encryption instead of RC4 (Used by WEP and WPA)
* AES is the encryption standard for the US Government and is used Worldwide.
138
WPA2 Modes?
WPA2 supports 2 Modes:
• WPA2 Personal Mode (WPA2-PSK) -- Pre-Shared Key for Home use.
• WPA2 Enterprise Mode (WPA2 with 802.1x) -- Provides authentication services via a Windows Server before users are granted access to the wireless network.
139
Wide Area Networks (WANs)?
WANs connect smaller networks together.
• Typically covers a relatively broad geographic area.
• Uses transmission facilities provided by common carriers.
• You usually lease a WAN infrastructure from a Service Provider.
```
Common WAN Technologies
• Circuit Switching
• Packet Switched Virtual Circuits
• Leased Lines
• Cell Relay
```
140
Circuit Switching?
* Designed in 1878, was originally designed for Telephone Calls.
* Uses a dedicated Point-To-Point Connection (circuit) using a telecommunications network.
* A circuit guarantees you full bandwidth of the circuit and remains connected for the duration of your call.
* The circuit functions as if the nodes were physically connected as with a dedicated electrical circuit.
141
Packet Switching?
* Uses virtual switch that provide end-to-end connectivity.
* Data is moved in packets based on the destination address in each packet.
* Unlike circuit switching, packet switching shares bandwidth and connection with others.
* This method of data transmission is the core technology for the Internet and most LANs.
142
Dial-Up Connection?
* The Original Internet Connection methodology.
* 56kbps (Kilobytes per second) max speed.
* Uses POTS (Plan Old Telephone Services) also referred to as a PSTN (Public Switched Telephone Network)
* Utilizes Circuit Switching.
143
ISDN?
Integrated Services Digital Network (ISDN)
• The original High Speed Internet Connection.
• A POTS Network System that operates via circuit-switched technology.
• Can simultaneously transmit data and phone conversations digitally over normal telephone wires.
With Dial-Up you could not make phone calls while accessing the internet.
With ISDN, you can make phone calls and access the internet simultaneously.
144
ISDN Basic Rate Interface (BRI)?
* Uses two data (Bearer or B) channels that operate at 64Kbps for a total data transfer rate of 128Kbps for uploads and downloads.
* Also has a 16Kbps D channel that transmits control information.
145
ISDN Primary Rate Interface (PRI)?
A High Speed form of ISDN - provided a T1 and E1 Trunk Lines.
• T1: USA, Canada, Japan, and E1: Europe.
T1 Trunk Line is divided into 24 channels of 64Kbps capacity (1.544Mbps)
• 23 64Kbps B Channels and 1 64Kbps D Channel.
E1 Trunk Line is divided into 32 Channels of 64Kbps capacity (2.048Mbps):
• 30.64Kbps B Channels and 2 64Kbps D Channels
146
T-Carrier and E-Carrier Digital Signal Lines?
* A Single Digital Signal is 64Kbps - Single DSO Channel.
* T1/E1 and T2/E3 utilize multiple 64Kbps channels to provide high-speed connectivity.
Commonly referred "Dedicated" leased lines, because they are leased from the telecommunications company to provide a dedicated circuit.
• Circuit-Switched Technology
147
Comparing T1, E1, T3, and E3 Speeds?
DSO ---------------- 64Kbps -------------- Single Channel
T1 (DS1) ------------ 1.544Mbps ---------- 24 DSO 64Kbps Channels
E1 (DS1) ------------ 2.048Mbps --------- 30 DSO 64Kbps Channels
E3 (DS3) ----------- 34.368Mbps ------- 512 64Kbps Channels
T3 (DS3) ----------- 44.736Mbps -------- 672 64Kbps Channels
148
DSL?
Digital Subscriber Line (DSL)
• High-Speed Internet Technology utilizing POTS
• Sends data digitally over telephone lines.
• Utilizes a DSL Modem and a Splitter to accomplish this Task.
DSL Limitation:
• DSL Modem must be within 2 miles of telecommunications company's central office (CO).
149
SDSL vs ADSL?
Symmetric DSL (SDSL)
• Provides Equal bandwidth for downstream and upstream data flows.
• 1.544Mbps (US and Canada) - T1 Equivalent
• 2.048Mbps (Europe) - E1 Equivalent
```
Asymmetric DSL (ADSL)
• Allocates more bandwidth to downstream than upstream data flows.
• 1.544 to 6.1Mbps downstream and 16 to 640Kbps upstream.
```
150
Broadband Cable?
High-Speed Internet Technology utilizing your cable service.
• Data Over Cable Service Interface Specification (DOCSIS)
• Standard to provide internet access via a cable modem.
Understand broadband
• The simultaneous transmission of multiple signals over different frequencies at the same time.
• This allows for different cable TV channels and your internet data to be assigned to different frequencies, all being transmitted simultaneously.
151
Broadband Cable DOCSIS Standards?
Version Download Upload Speed
1. 0 ----------------- 40Mbps -------------- 10Mbps
1. 1 ------------------ 40Mbps -------------- 10Mbps
2. 0 ---------------- 40Mbps -------------- 30Mbps
3. 0 ---------------- 1.2Gbps --------------- 200Mbps
3. 1 ----------------- 10Gbps ---------------- 1Gbps
3. 1 Full Duplex - 10Gbps --------------- 10Gbps
152
X.25?
* The original packet switching technology designed in the 1970s
* 2400bps - 2Mbps data transfer rate.
153
Frame Relay?
* Advancement of X.25 designed in the 1990s.
* Has a base price on its committed information rate (CIR)
* Puts data in a variable-sized unit called a Frame.
* T1 (1.544Mbps) & T3 (44.736Mbps) data transfer rates.
* Discontinued by major internet service provides from 2007 through 2016.
154
ATM?
* Asynchronous Transfer Mode (ATM)
* An advanced packet switching technology, called cell-Based" switching Technology
* Utilizes fixed length packets (53 bytes)
* Can be used with Fiber Distribution Data Interface (FDDI), Synchronous Optical Network (SONET), and other high speed WAN technologies.
* Speeds on ATM networks can reach 10Gbps
155
FDDI?
* Fiber Distributed Data Interface (FDDI)
* Standard for transmitting on fiber optic cables at 100Mbps.
* Was primarily used on backbone networks, but was made obsolete by Fast Ethernet in the 1990s, which offers the same speeds a much lower cost.
156
SONET/OCx?
* Synchronous Optical Networking (SONET)
* Designed to carry large volumes of data over long distances via fiber optic cabling.
* Capable of supporting data transfer rates in gigabit range.
157
Intranet and Extranet?
Intranet
• An organization's internal private network that only the organization's employees can access.
• Used for internal business activities such as HR, accounting, R&D, etc.
Extranet
• A portion of an organizations private network that only business partners can access.
• Used for business partner activities such as ordering supplies, etc. Via a business partner web portal.
158
Perimeter Network: DMZ?
• A small network designed to be securely separated from an organizations intranet.
• It's commonly called a DMZ (Demilitarized Zone)
• Allows untrusted users outside an organizations LAN (Intranet) to access specified services located within the DMZ.
Public Web Site(s)
Trivial FTP Server for File Downloads (Drivers, Software, Etc.)
Public Email Services (GMAIL, ETC.)
• Also blocks such users from gaining access to the organizations intranet.
159
2 Configs for DMZ Perimeter Networks?
3-Leg DMZ Config
• Internet > Router > FIREWALL > Server > Then Intranet
Back-To-Back DMZ Config
• Internet > Router > FIREWALL > Server > FIREWALL > Then Intranet
160
Firewalls?
* Protect your LAN from Malicious Activity on the Internet
* Prevents Unwanted Network Traffic on Different Networks from Accessing your network and vice versa
* Essentially controls the flow of information in and out of your Network.
* You create network access rule sets to setup and maintain a firewall.
* A firewall can be a standalone network device or software on a computer system, meaning network-based or host-based.
161
1st Generation: Packet Filtering Firewall?
The Original type of Firewall and most basic type of Firewall.
• Filters packets based on IP Addresses and ports.
162
2nd Generation: Stateful Inspection Firewall?
* Analyzes packets similar to a packet filtering Firewall; however, it also make intelligent decisions tracking each communication session.
* Determine the legitimacy of a requested session by monitoring the 3-way handshake between packets.
* Hackers can alter the 3-way handshake process attempting to cause Denial of Service (DoS) attacks.
* If the Firewall believes an attack is occurring, it will block the traffic.
163
3rd Generation: Application Layer Firewall?
* Filters packets based on an Application or Service.
* It "Understands" certain applications and protocols (FTP, DNS, HTTP, Etc..) and is able to detect if an unwanted application or service is attempting to bypass the Firewall using a protocol of a different port.
164
Intrusion Detection & Prevention Systems?
Are designed to detect attacks on a network and respond passively or actively.
Basic Firewalls will try to block network attacks using ACLs (Rules) while IDS/IPS will try to detect the attacks.
• IDS is Passive, meaning its response is logging and notifying.
• IPS is Active, meaning it'll change the network environment to stop an attack, such as changing ACLs or closing processes, sessions, or ports.
165
Proxy Servers?
• Acts on behalf of computers within a LAN to retrieve web content from the Internet.
• Specifically, proxy servers can provide the following services.
Filtering
Content Checking
Caching
166
Virtual Private Network (VPN)?
Allows you to connect to a private network over a pubic network in a secure, encrypted manner.
Once connected to the Internet with a public IP address, a tunneling protocol is used to create a protected tunnel through the Internet to the VPN server.
Tunneling basically means encapsulating one protocol within another to ensure that a transmission is secure.
167
Types of VPN?
Remote Access VPNs
• Allows remote users such to securely access an organizations Internal Network (Intranet) wherever and whenever they need to.
Site-To-Site VPNs (Intranet VPNs)
• Allows an organization to connect its remote sites to the corporate office securely over the internet.
168
VPN Tunneling Protocols?
Point-To-Point Tunneling Protocol (PPTP)
• Has known vulnerabilities, so it is falling into disuse in favor of L2TP.
• Was commonly used by Microsoft and Encrypted via Microsofts Point-To-Point Encryption.
• Uses TCP Port 1723.
Layer 2 Tunneling Protocol (L2TP)
• The most common tunneling protocol today.
• Doesn't encrypt data itself, but relies on IPSec to encrypt data.
• A downside to IPSec is that it cannot traverse NAT.
• Uses UDP Port 1701.
Secure Socket Tunneling Protocol (SSTP)
• Used to encrypt PPTP or L2TP traffic using SSL over Port 443.
• Was developed to overcome IPSec's incompatibility with NAT.
169
IPConfig?
Used to display or alter a computer's TCP/IP Configuration.
```
/all = Displays the Config of all network interfaces
/release = Releases IPv4 DHCP lease.
/release6 = Releases IPv6 DHCP lease.
/renew = Renews IPv4 DHCP lease.
/renew6 = Renews IPv6 DHCP lease.
/displaydns = Displays Host's DNS Cache.
/flushdns = Removes Host's DNS Cache.
```
170
Netstat?
Identifies a computer's listening ports, along with incoming and outgoing network connections.
- a = Shows all connections and listening ports.
- b = Shows connections that all applications are using to connect to the network.
- e = Shows Ethernet Stats.
- f = Shows fully qualified domain names.
- r = Shows routing table.
171
PathPing?
Combines the functionality of Ping and Tracert.
It provides details on the path between two hosts and Ping-Like stats for each node in the path.
- 4 = Forces use of IPv4
- 6 = Forces use of IPv6
- n = Suppresses name resolution so only IP addresses are listed.
- q = Changes the number of queries per hop.
172
PING?
Used to test communication over IP to another host via sending out an echo request.
- 4 = Forces use of IPv4
- 6 = Forces use of IPv6
- t = Continues pinging until stopped.
- a = Resolves IP Addresses to Host Name
- w = Changes the default timeout period.
173
Tracert?
Similar to PING, except that it reports back from each router on the path between your client computer and the remote host.
- 4 = Forces the use of IPv4
- 6 = Forces the use of IPv6
- d = Suppresses name resolution so only IP addresses are listed.
