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WINDOWS: SYSTEM ADMIN > NETWORKING (Basics) > Flashcards

NETWORKING (Basics) Flashcards

1
Q

What is Networking?

A

Network: It is a group of systems connected together sharing information

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2
Q

What is IT?

A

IT (information Technology): It is the use of technology (hardware and software) to create, store and manage data

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3
Q

What is the Internet?

A

Internet: - It is a group of LANs connected together spanning the globe or any network made public connected to other networks

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4
Q

?What are the 3 Types of Networks

A

Types of Networking
LAN – is a group of systems connected together sharing data spanning a small geographical area
MAN – is a group of LANS connected together sharing data spanning a metropolitan area
WAN - – is a group of LANS connected together sharing data spanning a wide area

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5
Q

What is a LAN?

A

LAN – is a group of systems connected together sharing data spanning a small geographical area

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6
Q

What is a MAN?

A

MAN – is a group of LANS connected together sharing data spanning a metropolitan area

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7
Q

What is a WAN?

A

WAN - – is a group of LANS connected together sharing data spanning a wide area

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8
Q

List 2 Categories of Networking

A
  1. Peer to Peer Network (P2P Network)

2. Client Server Network

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9
Q

What is a P2P Network?

A

Peer to Peer Network (P2P Network)

  1. It is a group of systems connected together sharing data without a central server involved
  2. Systems within P2P Network talk and exchange information but have no server
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10
Q

What is a Client Server Network?

A

Client Server Network

  1. It is a group of systems connected together sharing data with a central server involved
  2. Usually found in businesses
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11
Q

What is a DHCP?

A

DHCP (Dynamic Host Configuration Protocol)
– It assigns network configuration settings or information to network systems. For example, Default Gateway, IP Address, DNS address etc
– It assigns IP address, Default Gateway address and DNS addresses (constitute network configuration settings)
– It leases out dynamic IP addresses to networked system
– The default DHCP lease duration in Windows is 8 days
– Admin can change the lease duration to DHCP

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12
Q

List and Describe 2 Types of VMware

A

VMware Review
2 Types of VMware

  1. Hosted Hypervisor
    It is loaded onto an existing OS, and operates like an application type hypervisor
    Eg Oracle VirtualBox VMware
  2. Baremetal Hypervisor
    Loaded onto an existing physical system operates like a OS type Hypervisor
    Eg. Esxi VMware
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13
Q

How do you check the default DHCP lease duration in Windows?

A

Check out default DHCP lease duration

Search bar/Command Prompt/Ipconfig /all

See Output:
DHCP Enabled: Yes (Means you have a dynamic IP Address)
Lease Duration: Monday March 2, 2020 737pm
Lease Expires: Wednesday March 4th 2020 631pm

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14
Q

What is the difference between a P2P and a Domain?

A

A domain deals with a client server and a P2P Network deals with workgroups not connected to a client server

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15
Q

What is a Default Gateway?

A

Default Gateway

  1. It is the system that connects the LAN to the world or internet
  2. It communicates with Systems within the network and systems outside of the network and brings and sends information from the internet
  3. A router can be a default Gateway only if it is connected to the internet
  4. ISP (Internet Service Provider) DHCP assigns public IP address to router
  5. The public IP of the gateway router enables internet systems to communicate with the LAN
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16
Q

How do you display an IP address on a computer?

A

Search bar/Command Prompt/ipconfig

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17
Q

What is an IP Address?

A

IP Address: it is a unique number assigned to a system within a network by the DHCP

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18
Q

How do you display a public IP Address of your system?

A

Go to browser/type “whatismyip.com” or “ipchicken.com”

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19
Q

How can you display all shared resources in your system?

A

Search bar/Command Prompt/localhost

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20
Q

Troubleshooting Internet Connection Issues

A

TROUBLESHOOTING

  1. Customer cannot connect to the internet
Troubleshoot by Elimination
a) Are you the only one who cannot connect to the internet?
Yes.      
-	Not Default Gateway
-	Not a network issue
-	Could be cables, ports, NIC, system related problem, software or hardware issue
NO.
–	Could be Default Gateway
–	Could be switch, router, DHCP, or ISP
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21
Q

How do you quickly check if ISP is down?

A

ping facebook.com

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22
Q

What does IP in IP Address stand for?

A

IP address – Internet Protocol address

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23
Q

How do you display an IP address on a computer?

A

Search bar/Command Prompt/ipconfig

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24
Q

How can you display all shared resources in your system?

A

Search bar/Command Prompt/localhost

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25
Q

How can you display Detailed Configuration Settings Information?

A

Search bar/Command Prompt/ipconfig /all

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26
Q

How can you Clear the Command line?

A

Search bar/Command Prompt/cls or clr ot clear
(windows, Linux and Unix)
.

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27
Q

What is a Fully Qualified Domain Name?

A

Fully Qualified Domain Name (FQDN)
– It is the hostname and domain name of a system
– For example, Entire name: class26.trinitechglobal.com - Hostname – class26 + Domain – trinitechglobal.com
ge to take effect

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28
Q

WHat is a Workgroup?

A

WORKGROUP
– It is a group of systems in a P2P network sharing information
– It is a subset of a P2P network
– Only systems in a specific workgroup can share information or resources
–

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29
Q

How can you find and change a Workgroup Name?

A
  1. Find workgroup name
    File explorer/ Right click This PC/Properties/Workgroup name
  2. Change workgroup Name
    File explorer/ Right click This PC/Properties/Workgroup name/Change Settings/Change

Need to reboot for name change

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30
Q

How to change Dynamic IP address to Static IP Address

A

Right Click Network Icon/Network + Sharing Center/Change Adapter (another Name for NIC)/Right click WIFI/Properties/IPv4/Properties/Enter desired IP address ( it will not show here because you have dynamic IP address)
- Disconnect IPv6 to increase internet speed

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31
Q

What identifying label to computers use to communicate with each other?

A

COMPUTERS COMMUNICATE BY IP ADDRESSES

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32
Q

What is the term used to refer to the identifying label that humans use for computer or systems in a network?

A

HUMANS COMMUNICATE BY HOSTNAMES

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33
Q

What is a Hostname?

A

Hostname: - It is a label assigned to a system by an Admin

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34
Q

List and Describe the 5 Different DNS Records

A
  1. A record (IPv4) is a HOSTNAME to IP Address mapping used for FORWARD NAME RESOLUTION (Name Resolution) for IPv4
  2. AAAA record (IPv6) is a HOSTNAME to IP Address mapping used for FORWARD NAME RESOLUTION for IPv6
  3. PTR record (pointer record) is used for DNS reversed name resolution (IP Address to HOSTNAME mapping used for REVERSE NAME RESOLUTION)
  4. cName record (canonical Name) is used to create HOSTNAMEALIASES to IP Address mapping in the DNS used for FORWARD LOOK UP ZONE eg. Hostname – PCI (IP Address 192.168.2.4) – A record & CNAME = Mike (IP Address 192.168.2.4) - Cname Record
  5. MX record (Mail Exchange record) is used to identify an email in the LAN (Microsoft Exchange Email Server)
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35
Q

What happens if DNS does not create an A record?

A

If DNS does not create an A record for a system then the system will not be able to connect with other systems using a HOSTNAME

A hostname will not work to map drive to system B if there is no A record mapping it to an IP address

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36
Q

What is a Layer 3 Switch?

A

LAYER 3 SWITCHES: - Includes switch, router, DNS, Default Gateway, DHCP
For a Layer 3 Switch, the DHCP Server, DNS and Default Gateway will all have the same IP address because they are all part of the same unit (layer 3 switch)

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37
Q

List the 5 DNS Records

A
  1. A records
  2. AAAA records
  3. Pointer Records
  4. MX Records
  5. cName records
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38
Q

List the 5 DNS Records

A
  1. A records
  2. AAAA records
  3. Pointer Records
  4. MX Records
  5. cName Records
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39
Q

What is an AAAA (4A) record?

A

AAAA (4A) record: - - It is a hostname to IP Address mapping for IPv4

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40
Q

What is stored in the Forward Lookup Zone of the DNS Server?

A

A and AAAA records are stored in the FORWARD LOOKING ZONE of the DNS server

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41
Q

What is a Forward Name Resolution?

A

Forward Name Resolution

It is a Hostname to IP Address resolution

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42
Q

What is a Reverse Name Resolution?

A

Reverse Name Resolution

It is an IP address to Hostname resolution

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43
Q

Describe how DNS stores records in the Forward Lookup Zone from when the DHCP sends out a broadcast request signal?

A

Where are the records stored?

  1. DHCP sends a broadcast Request Signal to all systems in the LAN
  2. It then assigns IP addresses or Network Configuration settings for all systems in the LAN.
  3. Every system in the LAN that is configured by the DHCP will have an A or AAAA record (or both).
  4. These records are generated in the DNS when the local systems register themselves with the DNS server after receiving their Network Configuration settings from the DHCP
  5. These records are stored in the FORWARD LOOKING ZONE of the DNS server
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44
Q

How does DNS get A records?

A

When a local system registers with the DNS after receiving its network configuration settings from the DHCP

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45
Q

What is a DHCP Request Broadcast?

A

DHCP Request Broadcast: - It is a signal sent to all systems in a LAN by the DHCP requesting

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46
Q

What are Network Configuration Settings?

A

Network Configuration Settings:- are generated by the DHCP for every system in the LAN. They include an IP address, MAC address, Default Gateway IP address,

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47
Q

What is the difference between a P2P and a Domain?

A

A domain deals with a client server and a P2P Network deals with workgroups not connected to a client server

Peer to Peer Network

  1. It is a group of systems connected together sharing data without a central server involved
  2. Systems within P2P Network talk and exchange information but have no server
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48
Q

List and Describe the 2 Types of DOmains?

A

DOMAINS
2 Types of DOMAINS
1) Local Domain
– It is a group of systems connected together sharing information controlled by a central server called a Domain Controller
– A domain admin manages the domain controller
– Local domain prefix – “domain name.local”
– What is the prefix of a local domain?
.local

2) Public Domain
– It is created by a domain hosting company and is used to host websites and web applications
– Public domain prefixes - .com, .org, .net, .info, .gov
– Most popular public domain hosting companies – godaddy.com or Bluehost

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49
Q

List and Describe the 2 Types of Domains?

A

DOMAINS
2 Types of DOMAINS
1) Local Domain
– It is a group of systems connected together sharing information controlled by a central server called a Domain Controller
– A domain admin manages the domain controller
– Local domain prefix – “domain name.local”
– What is the prefix of a local domain?
.local

2) Public Domain
– It is created by a domain hosting company and is used to host websites and web applications
– Public domain prefixes - .com, .org, .net, .info, .gov
– Most popular public domain hosting companies – godaddy.com or Bluehost

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50
Q

What is a Public IP address?

A

Public IP Address: - It is an IP address that is used across the entire Internet to locate computer systems and devices.

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51
Q

What is an IP Conflict?

A

IP Address Conflict: - It is when 2 systems in a LAN have the same IP address making them unable to communicate

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52
Q

RECOMMENDATION FOR NON MOVING SYSTEMS IN A NETWORK

A

RECOMMENDATION: DHCP and Router IP Addresses should always be static IP Addresses. DHCP IP address is assigned by the Admin. Static IP addresses should be assigned to non moving systems

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53
Q

More

A 
DHCP Scope
It is the range of IP addresses that an be assigned to network system by DHCP	
-	IP SCOPE
Starting IP: - 192.168.2.10
-	Ending IP: - 192.168.2.200

IP of 4th octet —- 1 to 254 possible = 2^n-2
Assign IP Addresses outside scope to Network routers, DHCP, etc

DHCP Reservations
- When you tell DHCP to always assign a specific IP address to a specific System
- Still a dynamic IP address but it is reserved
- Is a Reserved IP Address dynamic or Static?
- Dynamic
- Static IP Address: It is assigned by admin and remains permanent whether at work or at home
- Dynamic IP Address: It is assigned by DHCP and changes
- Reserved IP Address: - Will always be assigned when at work but changes at home
- No one else will get this IP Address even if user is away
IMAGES
IMAGES
Default Gateway address is your local IP Address assigned by DHCP
VPN (Virtual Private Network) – ISP still collects your data
Public IP assigned by ISP
 
TCP/IP (Transport Control Protocol /Internet Protocol)
TCP (Transmission or Transport Control Protocol) : - It is considered a data transporter. It transmits data from one system to another
IP (Internet Protocol): - It is considered a data carrier

 					TCP (Data Transporter)

What is the Difference between TCP and UDP?
TCP is connection oriented because it establishes a connection between sender and receiver before data is sent. This makes it more secure and slower. Retransmission possible.
UDP is a connection that does not establish a connection before sending data making it faster, and not reliable. Retransmission is not possible with UDP transmission
WINSCP: It works with TCP and IP to transmit information
TCP/IP Troubleshooting Tools
Or Networking Troubleshooting Tools
WINDOWS COMMANDS
1. Ipconfig
a. Displays limited network configuration information
2. Ipconfig /all
a. Displays detailed network configuration information (all)
b. For example, it displays DNS, Default Gateway, DHCP lease, and DHCP information
3. Ipconfig /release
a. It will drop an IP Address of a system
b. This system will drop off the internet or LAN
c. Using /release/renew will cause system to lose IP Address, and connection to the server to download if in the middle of a download (may prefer /flushdns if halting internet or halting download would be a problem)
4. Ipconfig /renew
a. It will request a new DHCP IP Address for a system
5. Ipconfig /flushdns
a. It clears DNS information from the RAM
b. It clears DNS information in the RAM cache which will force DHCP to create a new DNS
c. This would help you in a situation where DNS 1 is down and need to use DNS2 backup
d. Either reboot or use this command to delete all DNS information when you cannot reboot (like for a server)
e. In Business setting usually create primary and secondary DNS so when one goes down use the other one
f. Google Free DNS servers: Google 8.8.8.8 or Google 8.8.4.4 – They will resolve public hostnames only and not local hostnames. These are used as secondary DNS which will serve as a backup when DNS is down
g. IMAGES
h. IMAGES
6. Ping
a. It is a tool used to test or check for connectivity between 2 network systems
b. It checks if your system is connecting to my system? Or the internet? Or the DNS server?
c. For example when you ping Google.com should get response with google Ip address ping
7. Up arrow
a. It will recall the previous command line
b. Same in LINUX/UNIX systems in Bash shell
8. Nslookup (Name Server Lookup)
a. It is used to query the DNS database for information in the database
9. Nslookup
a. It will search the DNS Database for the IP address associated with the hostname
b. A forward lookup is performed in DNS involving an A record
c. Hostname to IP Address is a forward Lookup involving a A record
10. Nslookup
a. It will search the DNS database for the hostname associated with IP Address
b. A Reversee lookup is performed in DNS involving a PTR (pointer) Record
c. IP Address to Hostname is a reverse lookup involving a PTR record
11. Arp -a
a. It displays an arp table or current ARP entries
12. cls
a. It clears command line in Windows
13. clr
a. It clears command line in LINUX/UNIX
14. arp /a
a. It displays the arp Table or current ARP entries
15. arp /v
a. It displays the arp Table or current ARP entries in verbose mode
b. Admin level
16. inet addr
a. Specifies internet addresss
17. N if addr
a. It displays the ARP entries for the network interface
18. Ipconfig /allcompartments
a. It displays the information about all compartments
19. Ipconfig /allcompartments /all
a. It displays the detailed information about all compartments
20. Tracert
a. It is used to display the path of traffic flow or flow of traffic from sending system to the receiving system across a maximum of 30 routers or hops
b. Pronounced Trace it
c. You cannot trace them if they are in the cloud (Cloud does not have backbone problems (central support to rest of the system)
d. Tracert Output looks like: 1 8ms 10ms 8ms Fios (192.168.2.1)
21.

Non authoritative answer
This is when the response is not an admin response but a receiving system answer
“Server Unknown” response which comes with an IP address is likely due to a firewall
Bandwidth:- Maximum rate of transfer of data across a given path or medium
Bandwidth issue: - When bandwidth provided limits the amount and speed of data transfer slowing down information access
ARP (Address Resolution Protocol)
a. It maps IP Addresses to MAC addresses
MAC ( Media Access Control) or Hardware address or ethernet address or Physical address
a) A MAC address is a unique alphanumeric (uses number as and letters)address assigned to a network device by the vendor
b) Phone has a MAC address
c) NIC, router or switch has MAC address
How do you get a Mac Address of a System?
a) Search bar/Command Prompt/arp -a (check arp table)
b) If not there, ping system then arp -a it will display MAC address
How do you display an ARP table in Windows?
Search bar/ Command Prompt/Arp -a
Output
IP Address MAC address Type

192.168.56.255
ff-ff-ff-ff-ff-ff
Static

How do you display or trace path of traffic flow?
a) Search bar/Command Prompt/tracert
Troubleshoot Networking Problem: If the Folks in NY cannot connect, is the server down?
HQ

MD Webserver IP: - 10.7.8.7

  1. Ping NY IP Address (10.7.8.7)
    a. If you get a response, then network is not down
  2. Call field office in GA
    a. Yes can access network
  3. Call NY Field office
    a. Cannot Access Network
    b. So what is the problem?
  4. Tracert 10.7.8.7 (NY IP Address)
    a. Tracert drops in NJ field office (see error message: Request Timed Out)
    b. If get timed out but continues to receiving system then that means a firewall is not releasing the information
    c. If it just stops at field office then problem may be at that field office
  5. Call NJ Field Office
    a. Let you know Verizon down in area
    b. Call Verizon. Get Ticket #: 344AC3
    c. Find dour how soon problem will be resolved from Verizon
    d. Create in-house ticket
    e. Always be thorough

PING
a. It is a tool used to test or check for connectivity between 2 network systems
b. Even if we get one response out of 4 requests it is a positive ping
c. If you can ping a system, then it is not a network connectivity issue
d. Sometimes lose packets when you ping because of internet traffic congestion (means it takes forever for signal to get to receiver)
IMAGES
IMAGES
A positive ping:
a) It is when the receiving system responds to a ping request from the sending system
b) It receives replies and a positive round trip information from receiving system
A negative ping: -
a) It is when the receiving system does not respond to a ping request from the sending system

Negative Ping Response Types:
1. Request timed Out for all 4 requests
2. Destination host Unreachable for all 4 requests
ICMP (Internet Connection Messaging Protocol): It is responsible for transmitting ping traffic
Typical Ping Response
Reply 8.8.8.8 bytes =32 time 7ms TTL =54
Bytes =32 – Amount of data sent
Time -=7ms - Time it took to respond (returning time)
TTL (Time to Live)
a) It is the maximum time allows for the receiving system to respond to the ping signal before it is dropped by the sending system eg TTL = 54ms – means it will be dropped after 54 ms
b) It is set by system based on the internet traffic

IP Addressing

IP Address: - It is a number that is assigned to a system in a network by the DHCP or Admin that enables it to communicate with other systems in the network
If system Admin assigns an IP Address, it is STATIC
When DHCP assigns an IP Address, It is DYNAMIC
If it is a reserved IP Address, It is still DYNAMIC
Recommendation: System Hardware (eg Routers, Switch, Default Gateway) should be given only STATIC IP Addresses
TYPES OF IP ADDRESSES
Type Main Description
IPv4 It has about 4.7 billion IP addresses. It is made up of only numbers.
Ipv6 It has about 340 undercillion IP Address. It is made up of alphanumeric (both numbers and letters)

What is Undercillion? Million Billion Trillion Quatrillion Quintillion Sextillion Septillion Octillion Nonillion Decillion Undecillion What is the difference between IPv4 and IPv6 addresses? IPv4 1.	It is made up of only numbers 2.	It has no inbuilt security 3.	It is faster and that’s why it is used by System Admins 99% of the time as have enough Ipv4 addresses for a LAN 4.	Structure of IPv4:  X.X.X.X (where x is a number) IPv4 is……For example,	192.	168.	2.	1 4 Octets	Octet	Octet	Octet	Octet 32 bits	8 bits	8 bits	8 bits	8 bits 1 byte	1 byte	1 byte	1 byte	1 byte
  1. It is a 32 bit number assigned to a network system by an Admin or DHCP server in order to allow the system to communicate to LAN

IPv6
1. It has 128 bitalphanumeric IP addresses (have numbers and letters)
2. It has a lot more IP Addresses than IPv4 (only numbers)
3. It has an inbuilt security called IPSEC
4. It is more secure and slower in data transmission due to security overhead included in IPv6
5. It is mostly used by ISPs (internet Service Providers)
6. Mainly dealt with by Cisco Adminss who go into details into IPv6 and its structure
7. How do you disconnect an IPv6 address?
a. Search bar/Control Panel/Network and Internet/Network & Sharing Centere/Change adaptor settings/Right Click NIC/Properties/Disconnect or unselect IPv6
IPv4 Classes
Helps you troubleshoot Ip related issues
Classes First Octet Range
X.-.-.-. eg 192.1.1.1 Subnet Mask Function
Class A
1-126 255.0.0.0 Used for computers
LOOPBACK ADDRESS
(reserved for Loopback Address) 127
127.0.0.1 N/A It is referred to as the local host. It is used to troubleshoot the Ip Stack of a system eg Windows or LINUX
Class B
128-191 255.255.0.0 Used for computers
Class C
192-223 255.255.255.0 Used for computers
Class D
224-239 N/A Used for Broadcasting and Multicasting
Class E
240-255 N/A Used for Research

Broadcasting: - It is sending something to every system in a network

Subnet Mask:

  1. it is used to separate the network address portion from the host address portion
  2. The IP address has 2 parts
    a. Network address portion which is always STATIC (defines the LAN address)
    b. Host address portion which is always dynamic
  3. The IP address can only be separated by subnet mask

ONLY SYSTEMS WITH SAME NETWORK ADDRESS CAN TALK TO EACH OTHER. !!! This is important for troubleshooting Networking issues !!!

Examples: NOTE:255s in subnet mask determine Network address and 0s determine the Host address
First Octet determines Class

CLASS B
172 168 2 4 IP Address
255 255 0 0 Subnet Mask
Network address: 172.168 Host Address: 2.4

CLASS A
10	3	7	1	IP Address
255	0	0	0	Subnet Mask 
Network address:
10  	     Host Address:                3.7.1	
CLASS C
192	168	2	10	IP Address
255	255	255	0	Subnet Mask 
Network address:                      192.168.2	Host Address:
10

IMAGES
IMAGES

  1. 168.2.10 192.168.2.11 WHAT IS THE PROBLEM?
  2. 255.255.0 255.255.255.0
  3. 168.2.12
  4. 255.0.0
  5. 168.2.10 192.168.2.11 WHAT IS THE PROBLEM?
  6. 255.255.0 255.255.255.0
  7. 168.2.12
  8. 255.0.0

PC Web Configurations Network Address NOTES
1 192.168.2.10
255.255.255.0 192.168.2 Able to connect to PC2 only. Same network address.
2 192.168.2.11
255.255.255.0 192.168.2 Able to connect to PC1 only. Same network address.
3 192.168.2.12
255.255.0.0 192.168 Cannot connect to PC1 and PC2 because it has a different network address (not in the same network) and needs a router to connect

Subnet mask set by Admin as Admin sets up DHCP and tells it what Class IP address is so DHCP will keep same network address for all assigned IP addresses For example, it will keep all first 3 octet numbers for Class C and only change 4th octet

CIDR (Classless Interdomain Routers)
1. It is used to conserve IP addresses.
2. It is used when the Standard IP class format is not respected
3. It can still route traffic but disregards the IP class conventions to conserve IP addresses
Address CLASS
IP Address 10.0.0.29 CLass A IP Address
Subnet Mask 255.255.255.0 Class C Subnet Mask

Some ISPs do this like Comcast – IP Address and Subnet Mask having 2 different classes that do not much
Total Number of IP Hosts

Formula: Total # of IP Hosts = 2n – 2
(n= Total # of host bits)

Class A (4th octet = 8bits)	28 -2 = 264
Class B	216 -2= 65534
Class C	224 -2 = 1.7 * 107
	Number of Computers or hosts that can be assigned a unique IP address under each class
For example
Class C 
IP Address 	192.168.1.2
Subnet Mask 	255.255.255.0
Host Address	x.x.x.2
Available Octet	x        x     x     8bits (to assign out)
264 hosts 
Class B
IP Address 	172.168.1.10
Subnet Mask 	255.255.0.0
Host Address	x.x.1.10
Available Octet	x   .     x   .  8bits  .   8bits (to assign out)
65534 hosts 
Class A
IP Address 	10.0.0.20
Subnet Mask 	255.0.0.0
Host Address	x.0.0.20
Available Octet	x   .     8bits  .  8bits  .   8bits (to assign out)
17 million hosts

Number Range in Each Ipv4 Octet

Eg. Ip Address  192.168.1.1
	Octet 1	Octet 2	Octet 3	Octet 3
4 Octets	Octet	Octet	Octet	Octet
32 bits	8 bits	8 bits	8 bits	8 bits
1 byte	1 byte	1 byte	1 byte	1 byte
NUMBER RANGE
AVAILABLE TO BE ASSIGNED IN EACH OCTET	1
.
.
.
.
.
126
128
.
.
.
.
223	0
.
.
.
.
.
255	0
.
.
.
.
.
255	1
.
.
.
.
254
Total Number	222	256 (includes 0)	256 (includes 0)	254

FAKE IP ADDRESSES
End with 1 or 255 or greater eg 192.162.2.256 or 192.162.2.0 or 192.162.1.0 (Invalid IP Addresses)
Loopback Address
127.0.0.1
1. It is referred to as a local host
2. It is used to troubleshoot the IP Stack of a system in Windows or LINUX
3. This is why the 1st octet cannot be assigned 127
IMAGES
IMAGES
IP Stack:
IMAGES
IMAGES (Notebook 3)
1. It is the program that runs the IP system of an operating system
2. Malware corrupts IP stack (or you can mess it up on your own) to make you unable to connect to the internet and so loopback address is used to troubleshoot a defective IP Stack
3. A positive loopback ping means the IP stack is good
4. A Negative loopback ping means the IP stack is bad
5. Also, if you cannot connect to the internet no matter what you do, then need to check if you have a bad IP stack

How do you troubleshoot a bad IP Stack

  1. Search bar/Command Prompt/ping 127.0.0.1
  2. If positive ping, then IP Stack is good
  3. If negative ping, then IP Stack is bad

How do we fix a Negative Loopback ping/bad IP Stack?

  1. In Windows
    a. Download, install and execute the winsock fix utility from Microsoft website. Free.
  2. In UNIX/LINUX
    a. Type: #sys-unconfig - in command line to fix bad IP Stack

Troubleshooting Network Issues
1. Network Related Issues – Default Gateway, DHCP, Firewall, Switch, Router
2. System Related Issues – Configuration, Software related issues, Hardware related issues, Malware Infection
Troubleshoot why you would not be able to ping 8.8.8.8?
1. NIC Problem
2. Default Gateway issue
3. Malware (Bad IP Stack)
4. Bad Cable
5. Router Firewall
6. No Internet blocked by ISP
7. IP Conflict
8. Bad IP
9. Network Configuration Error
Load Balancer
Why do you get 2 different IP Addresses for one domain like Facebook.com
Facebook.com Domain has load balancer, that can be daisy chained, that receives IP address request and sends request for IP address to least utilized server among multiple servers that are located globally.
 

										SERVERS

    192.168.1.1	192.168.1.2	192.168.1.1	192.168.1.1           192.168.1.1	IP ADRESSES
TOKYO, 	DUBLIN		NEW YORK	       BEIJING	   LONDON	LOCATION

This ensures that domain will not be overloaded
Most servers are set up like this
Syncronization/Clustering:
Information in each server is duplicated across servers. It could be across 1000s of servers.
 

54
Q

What does the #ping command do?

A

PING

a. It is a tool used to test or check for connectivity between 2 network systems
b. Even if we get one response out of 4 requests it is a positive ping
c. If you can ping a system, then it is not a network connectivity issue
d. Sometimes lose packets when you ping because of internet traffic congestion (means it takes forever for signal to get to receiver)

55
Q

How to identify Fake IP Addresses

A

FAKE IP ADDRESSES

End with 1 or 255 or greater eg 192.162.2.256 or 192.162.2.0 or 192.162.1.0 (Invalid IP Addresses)

56
Q

Troubleshooting Network Issues

A

Troubleshooting Network Issues

  1. Network Related Issues – Default Gateway, DHCP, Firewall, Switch, Router
  2. System Related Issues – Configuration, Software related issues, Hardware related issues, Malware Infection
57
Q

What is a loopback address?

A

Loopback Address

  1. 0.0.1
  2. It is referred to as a local host
  3. It is used to troubleshoot the IP Stack of a system in Windows or LINUX
  4. This is why the 1st octet cannot be assigned 127
58
Q

Troubleshoot why you would not be able to ping 8.8.8.8?

A

Troubleshoot why you would not be able to ping 8.8.8.8?

  1. NIC Problem
  2. Default Gateway issue
  3. Malware (Bad IP Stack)
  4. Bad Cable
  5. Router Firewall
  6. No Internet blocked by ISP
  7. IP Conflict
  8. Bad IP
  9. Network Configuration Error
59
Q

What is the DHCP Scope?

A 
DHCP Scope
It is the range of IP addresses that an be assigned to network system by DHCP	
-	IP SCOPE
Starting IP: - 192.168.2.10
-	Ending IP: - 192.168.2.200
  • IP of 4th octet —- 1 to 254 possible = 2^n-2
  • Assign IP Addresses outside scope to Network routers, DHCP, etc
60
Q

What does command #ipconfig do?

A

WINDOWS COMMANDS

  1. Ipconfig
    a. Displays limited network configuration information
61
Q

What does command #ipconfig /all do?

A

Ipconfig /all

a. Displays detailed network configuration information (all)
b. For example, it displays DNS, Default Gateway, DHCP lease, and DHCP information

62
Q

What does command #ipconfig /release do?

A

Ipconfig /release

a. It will drop an IP Address of a system
b. This system will drop off the internet or LAN
c. Using /release/renew will cause system to lose IP Address, and connection to the server to download if in the middle of a download (may prefer /flushdns if halting internet or halting download would be a problem)

63
Q

What does command #ipconfig /renew do?

A

Ipconfig /renew

a. It will request a new DHCP IP Address for a system

64
Q

What does command #ipconfig /flushdns do?

A

Ipconfig /flushdns

a. It clears DNS information from the RAM
b. It clears DNS information in the RAM cache which will force DHCP to create a new DNS
c. This would help you in a situation where DNS 1 is down and need to use DNS2 backup
d. Either reboot or use this command to delete all DNS information when you cannot reboot (like for a server)
e. In Business setting usually create primary and secondary DNS so when one goes down use the other one
f. Google Free DNS servers: Google 8.8.8.8 or Google 8.8.4.4 – They will resolve public hostnames only and not local hostnames. These are used as secondary DNS which will serve as a backup when DNS is down

65
Q

What is a DHCP Reservation?

A

DHCP Reservations

  • When you tell DHCP to always assign a specific IP address to a specific System
  • Still a dynamic IP address but it is reserved
66
Q

What is a Static IP Address?

A

Static IP Address: It is assigned by admin and remains permanent whether at work or at home

67
Q

What is a Dynamic IP Address?

A

Dynamic IP Address: It is assigned by DHCP and changes

68
Q

Is a Reserved IP Address dynamic or static?

A

Dynamic

69
Q

What is a Reserved IP Address?

A

Reserved IP Address: - An IP Address asigned to a specific user profile

  • Will always be assigned when at work but changes at home
  • No one else will get this IP Address even if user is away
70
Q

What is your local IP Address?

A

Default Gateway address is your local IP Address assigned by DHCP

71
Q

Who assigns a public IP address?

A

Public IP assigned by ISP

72
Q

What is TCP/IP?

A

TCP (Transmission or Transport Control Protocol) : - It is a data transporter that transmits data from one system to another

IP (Internet Protocol): - It is considered a data carrier that carriers the data that is being transported by the data transporter

73
Q

What is VPN?

A

VPN (Virtual Private Network) –

74
Q

Does ISP collect VPN data?

A

VPN (Virtual Private Network) – ISP still collects your data

75
Q

What does a positive ping?

A

A positive ping:

a) It is when the receiving system responds to a ping request from the sending system
b) It receives replies and a positive round trip information from receiving system

76
Q

What is a negative ping?

A

A negative ping: -

a) It is when the receiving system does not respond to a ping request from the sending system

77
Q

What does WinSCP do?

A

WINSCP: It works with TCP and IP to transmit information

78
Q

What is the Difference between TCP and UDP?

A

TCP (Transmission or Transport Control Protocol) is a data transporter that is connection oriented because it establishes a connection between sender and receiver before data is sent. This makes it more secure and slower. Retransmission possible.

UDP (User Datagram Protocol) is a connectionless communication protocol.
It is a connection that does not establish a connection before sending data making it faster, and not reliable.

Retransmission is not possible with UDP transmission

79
Q

How do you find the MAC Address of a System?

A

a) Search bar/Command Prompt/arp -a (check arp table)

b) If not there, ping system then arp -a will display MAC address

80
Q

What is a MAC Address?

A

MAC ( Media Access Control) or Hardware address or ethernet address or Physical address

a) A MAC address is a unique alphanumeric (uses number as and letters)address assigned to a network device by the vendor
b) Phone has a MAC address
c) NIC, router or switch has MAC address

81
Q

What is ARP?

A

ARP (Address Resolution Protocol)

a. It maps IP Addresses to MAC addresses

82
Q

How do you display an ARP table in Windows?

A

Search bar/ Command Prompt/Arp -a

Output
IP Address MAC address Type
192.168.56.255 ff-ff-ff-ff-ff-ff Static

83
Q

How do you display or trace path of traffic flow?

A

Search bar/Command Prompt/tracert

84
Q

What is a Non authoritative answer?

A

Non authoritative answer
This is when the response is not an admin response but a receiving system answer
“Server Unknown” response which comes with an IP address is likely due to a firewall

85
Q

What is Bandwidth?

A

Bandwidth:- Maximum rate of transfer of data across a given path or medium

86
Q

What is a Bandwidth issue?

A

Bandwidth issue: - When bandwidth provided limits the amount and speed of data transfer slowing down information access

87
Q

What does the command #ping do?

A
  1. Ping
    a. It is a tool used to test or check for connectivity between 2 network systems
    b. It checks if your system is connecting to my system? Or the internet? Or the DNS server?
    c. For example when you ping Google.com should get response with google IP address ping
88
Q

What does the command #nslookup do?

A
  1. Nslookup (Name Server Lookup)

a. It is used to query the DNS database for information in the database

89
Q

What does the command #nslookup do?

A

Nslookup

a. It will search the DNS Database for the IP address associated with the hostname
b. A forward lookup is performed in DNS involving an A record
c. Hostname to IP Address is a forward Lookup involving a A record

90
Q

What does the command #inet addr do?

A
  1. inet addr

a. Specifies internet addresss

91
Q

What does the command #clr or cls or clear do?

A

They clear the command line

  1. cls
    a. It clears command line in Windows
  2. clr
    a. It clears command line in LINUX/UNIX
92
Q

What does the command #arp/a do?

A

arp /a

a. It displays the arp Table or current ARP entries

93
Q

What does the command #arp/v do?

A

arp /v

a. It displays the arp Table or current ARP entries in verbose mode
b. Admin level

94
Q

What will the Up arrow do in the Windows Command Prompt?

A

Up arrow

a. It will recall the previous command line
b. Same in LINUX/UNIX systems in Bash shell

  1. Nslookup
    a. It will search the DNS database for the hostname associated with IP Address
    b. A Reversee lookup is performed in DNS involving a PTR (pointer) Record
    c. IP Address to Hostname is a reverse lookup involving a PTR record
95
Q

How do you troubleshoot a bad IP Stack?

A

How do you troubleshoot a bad IP Stack

  1. Search bar/Command Prompt/ping 127.0.0.1
  2. If positive ping, then IP Stack is good
  3. If negative ping, then IP Stack is bad
96
Q

How do we fix a Negative Loopback ping/bad IP Stack?

A

How do we fix a Negative Loopback ping/bad IP Stack?

  1. In Windows
    a. Download, install and execute the winsock fix utility from Microsoft website. Free.
  2. In UNIX/LINUX
    a. Type: #sys-unconfig - in command line to fix bad IP Stack
97
Q

What is an IP stack?

A

IP Stack:

  1. It is the program that runs the IP system of an operating system
  2. Malware corrupts IP stack (or you can mess it up on your own) to make you unable to connect to the internet and so loopback address is used to troubleshoot a defective IP Stack
  3. A positive loopback ping means the IP stack is good
  4. A Negative loopback ping means the IP stack is bad
  5. Also, if you cannot connect to the internet no matter what you do, then need to check if you have a bad IP stack
98
Q

List the IPv4 classes?

A

IPv4 Classes
Helps you troubleshoot Ip related issues

Class A
1-126 255.0.0.0 Used for computers

LOOPBACK ADDRESS
(reserved for Loopback Address) 127
127.0.0.1 N/A It is referred to as the local host. It is used to troubleshoot the Ip Stack of a system eg Windows or LINUX

Class B
128-191 255.255.0.0 Used for computers

Class C
192-223 255.255.255.0 Used for computers

Class D
224-239 N/A Used for Broadcasting and Multicasting

Class E
240-255 N/A Used for Research

99
Q

What does the command #Ipconfig /allcompartments do?

A
  1. Ipconfig /allcompartments

a. It displays the information about all compartments

100
Q

What does the command #Ipconfig /allcompartments /all do?

A

Ipconfig /allcompartments /all

a. It displays the detailed information about all compartments

101
Q

What does the command #tracert do?

A

Tracert
a. It is used to display the path of traffic flow or flow of traffic from sending system to the receiving system across a maximum of 30 routers or hops
b. Pronounced Trace it
c. You cannot trace them if they are in the cloud (Cloud does not have backbone problems (central support to rest of the system))
d. Tracert Output looks like:
1 8ms 10ms 8ms Fios (192.168.2.1)

102
Q

Troubleshooting: Using Tracert command to resolve connectivity issues in a MAN?

A

MD Webserver IP: - 10.7.8.7

  1. Ping NY IP Address (10.7.8.7)
    a. If you get a response, then network is not down
  2. Call field office in GA
    a. Yes can access network
  3. Call NY Field office
    a. Cannot Access Network
    b. So what is the problem?
  4. Tracert 10.7.8.7 (NY IP Address)
    a. Tracert drops in NJ field office (see error message: Request Timed Out)
    b. If get timed out but continues to receiving system then that means a firewall is not releasing the information
    c. If it just stops at field office then problem may be at that field office
  5. Call NJ Field Office
    a. Let you know Verizon down in area
    b. Call Verizon. Get Ticket #: 344AC3
    c. Find dour how soon problem will be resolved from Verizon
    d. Create in-house ticket
    e. Always be thorough
103
Q

List Negative Ping Response Types?

A

Negative Ping Response Types:
1. Request timed Out for all 4 requests
2. Destination host Unreachable for all 4 requests
ICMP (Internet Connection Messaging Protocol): It is responsible for transmitting ping traffic

104
Q

Typical Ping response

A

Typical Ping Response
Reply 8.8.8.8 bytes =32 time 7ms

TTL =54
Bytes =32 – Amount of data sent
Time -=7ms - Time it took to respond (returning time)

105
Q

What is TTL?

A

TTL (Time to Live)

a) It is the maximum time allowed for the receiving system to respond to the ping signal before it is dropped by the sending system eg TTL = 54ms – means it will be dropped after 54 ms
b) It is set by system based on the internet traffic

106
Q

IP Addressing?

A

IP Addressing

IP Address: - It is a number that is assigned to a system in a network by the DHCP or Admin that enables it to communicate with other systems in the network

If system Admin assigns an IP Address, it is STATIC

When DHCP assigns an IP Address, It is DYNAMIC

If it is a reserved IP Address, It is still DYNAMIC

Recommendation:
 System Hardware (eg Routers, Switch, Default Gateway) should be given only STATIC IP Addresses
107
Q

List the 2 Types of IP Addresses

A

TYPES OF IP ADDRESSES
Type Main Description
1. IPv4 It has about 4.7 billion IP addresses. It is
made up of only numbers.

  1. Ipv6 It has about 340 undercillion IP Address. It is
    made up of alphanumeric (both numbers and
    letters)
108
Q

What is a CIDR?

A

CIDR (Classless Interdomain Routers)
1. It is used to conserve IP addresses.
2. It is used when the Standard IP class format is not respected
3. It can still route traffic but disregards the IP class conventions to conserve IP addresses
Address CLASS
IP Address 10.0.0.29 CLass A IP Address
Subnet Mask 255.255.255.0 Class C Subnet Mask

Some ISPs do this like Comcast – IP Address and Subnet Mask having 2 different classes that do not much

109
Q

What is the total number of IP Hosts?

A

Total Number of IP Hosts

Formula:

Total # of IP Hosts = 2n – 2

(n= Total # of host bits)

Class A (4th octet = 8bits)	28 -2 = 264
Class B	                                216 -2= 65534
Class C	                                224 -2 = 1.7 * 107
	Number of Computers or hosts that can be assigned a unique IP address under each class

For example

Class C 
IP Address 	192.168.1.2
Subnet Mask 	255.255.255.0
Host Address	x.x.x.2
Available Octet	x        x     x     8bits (to assign out)
264 hosts 
Class B
IP Address 	172.168.1.10
Subnet Mask 	255.255.0.0
Host Address	x.x.1.10
Available Octet	x   .     x   .  8bits  .   8bits (to assign out)
65534 hosts 
Class A
IP Address 	10.0.0.20
Subnet Mask 	255.0.0.0
Host Address	x.0.0.20
Available Octet	x   .     8bits  .  8bits  .   8bits (to assign out)
17 million hosts
110
Q

What is Synchronization/Clustering:

A

Syncronization/Clustering:

Information in each server is duplicated across servers. It could be across 1000s of servers.

111
Q

What is a Subnet Mask?

A

Subnet Mask:

  1. it is used to separate the network address portion from the host address portion
  2. The IP address has 2 parts
    a. Network address portion which is always STATIC (defines the LAN address)
    b. Host address portion which is always dynamic
  3. The IP address can only be separated by subnet mask

ONLY SYSTEMS WITH SAME NETWORK ADDRESS CAN TALK TO EACH OTHER. !!! This is important for troubleshooting Networking issues !!!

Examples: NOTE:
255s in subnet mask determine Network address and 0s determine the Host address
First Octet determines Class

112
Q

What is Broadcasting?

A

Broadcasting: - It is sending something to every system in a network

113
Q

What is a load balancer?

A

Load Balancer
Why do you get 2 different IP Addresses for one domain like Facebook.com
Facebook.com Domain has load balancer, that can be daisy chained, that receives IP address request and sends request for IP address to least utilized server among multiple servers that are located globally.
 
SEVERAL SERVERS THAT RESPOND TO VOLUME OF REQUESTS

    192.168.1.1	192.168.1.2	192.168.1.1	192.168.1.1           192.168.1.1	IP ADRESSES
TOKYO, 	DUBLIN		NEW YORK	       BEIJING	   LONDON	LOCATION

This ensures that domain will not be overloaded
Most servers are set up like this

 

114
Q

What is the Problem

A. 192.168.2.10 / 255.255.255.0
B. 192.168.2.11 / 255.255.255.0
C. 192.168.2.12 / 255.255.0.0

A

Class C subnet mask of C is that of a class B subnet mask

Meaning its network address (198.162) which is different from the network addresses of the other 2 systems A & B (192.162.2) meaning system B (not in the same network) will be unable to directly communicate with the other systems and needs a router to connect

115
Q

What is the subnet mask?

A

Subnet mask set by Admin as Admin sets up DHCP and tells it what Class IP address is so DHCP will keep same network address for all assigned IP addresses For example, it will keep all first 3 octet numbers for Class C and only change 4th octet

116
Q

What is an IPv6 Address?

A

IPv6

  1. It has 128 bitalphanumeric IP addresses (have numbers and letters)
  2. It has a lot more IP Addresses than IPv4 (only numbers)
  3. It has an inbuilt security called IPSEC
  4. It is more secure and slower in data transmission due to security overhead included in IPv6
  5. It is mostly used by ISPs (internet Service Providers)
  6. Mainly dealt with by Cisco Adminss who go into details into IPv6 and its structure
  7. How do you disconnect an IPv6 address?
    a. Search bar/Control Panel/Network and Internet/Network & Sharing Centere/Change adaptor settings/Right Click NIC/Properties/Disconnect or unselect IPv6
117
Q

What is an Undercillion?

A

What is Undercillion?

Million Billion Trillion Quatrillion Quintillion Sextillion Septillion Octillion Nonillion Decillion Undecillion

118
Q

What is an IPv4 address?

A 
IPv4
1.	It is made up of only numbers
2.	It has no inbuilt security
3.	It is faster and that’s why it is used by System Admins 99% of the time as have enough Ipv4 addresses for a LAN
4.	Structure of IPv4:  X.X.X.X (where x is a number)
IPv4 is……For example,	192.	168.	2.	1
4 Octets	Octet	Octet	Octet	Octet
32 bits	8 bits	8 bits	8 bits	8 bits
1 byte	1 byte	1 byte	1 byte	1 byte
  1. It is a 32 bit number assigned to a network system by an Admin or DHCP server in order to allow the system to communicate to LAN
119
Q

What is the difference between IPv4 and IPv6 addresses?

A

What is the difference between IPv4 and IPv6 addresses?
IPv4
1. It is made up of only numbers
2. It has no inbuilt security
3. It is faster and that’s why it is used by System Admins 99% of the time as have enough Ipv4 addresses for a LAN
4. Structure of IPv4: X.X.X.X (where x is a number)
IPv4 is……For example, 192. 168. 2. 1
4 Octets Octet Octet Octet Octet
32 bits 8 bits 8 bits 8 bits 8 bits
1 byte 1 byte 1 byte 1 byte 1 byte

  1. It is a 32 bit number assigned to a network system by an Admin or DHCP server in order to allow the system to communicate to LAN

IPv6

  1. It has 128 bitalphanumeric IP addresses (have numbers and letters)
  2. It has a lot more IP Addresses than IPv4 (only numbers)
  3. It has an inbuilt security called IPSEC
  4. It is more secure and slower in data transmission due to security overhead included in IPv6
  5. It is mostly used by ISPs (internet Service Providers)
  6. Mainly dealt with by Cisco Adminss who go into details into IPv6 and its structure
  7. How do you disconnect an IPv6 address?
    a. Search bar/Control Panel/Network and Internet/Network & Sharing Centere/Change adaptor settings/Right Click NIC/Properties/Disconnect or unselect IPv6
120
Q

What is the OSI model?

A

OSI MODEL
a. What is the OSI model?
The Open Systems Interconnection model (OSI model)
1. It is a conceptual model created by the International Organization for Standardization (ISO) that enables diverse communication systems to communicate using standard protocols.
2. It provides a standard for different computer systems to be able to communicate with each other.
3. The OSI model is a universal language for computer networking,
4. It is based on the concept of splitting up a communication system into 7 abstract layers with each one stacked upon the last.
5. It is a set of standards or rules put together by the ISO to help developers build Oss that can talk to each other
6. It is a standard that facilitates the communication of different computer systems

121
Q

OSI MODEL additional

A

Nightmare for these systems to talk to each other

The Reason for the OSI Model is to help different OSs communicate with each other via a single protocol called TCP/IP

Protocol that was built out of OSI model is TCP/IP. Due to TCP/IP different operating systems can talk to each other

Open System Interconnect – systems can openly interconnect with each other due to the OSI model

122
Q

List the 7 layers of the OSI model

A

List the 7 layers of the OSI model
LAYER OSI MODEL Description Memorize
Layer 1 Physical Transmits raw bit stream over
physical medium. Processing
Layer 2 Data Link Defines the data format on the
network Data
Layer 3 Network Decided which physical path the
data will take Need
Layer 4 Transport Transmits data using
transmission protocols such as
TCP, UDP, To
Layer 5 Session Maintains connections and is
responsible for controlling ports and
sessions Seem
Layer 6 Presentation Ensures data is in a usable
format and where data encryption
occurs People
Layer 7 Application Human computer Interaction
layer – Where applications can
access Network services All

123
Q

Protocols and Devices used for each OSI Layer

A

OSI Layer Data PDU (Protocol Data Unit)
Protocols/devices
7 Application Data Http; FTP; NIS; DNS; LDAP,
Telnet, SNMP
6 Presentation Data Mpeg, jpeg, mp3, Unicode,
ANSI
5 Session Data SQL (queries), NFS, SSH, logins
occur at session layer
4 Transport *Segment TCP, UDP
3 Network *Packet Router IP, ARP, ICMP
2 Data Link Frame Switch, Bridge
1 Physical Bits (through Switches and cables) Hub,
NIC, Repeater

124
Q

Associate the following protocol with their port numbers

A

d. Associate the following protocol with their port numbers
Protocol *Port Number (memorize) Stands For
http 80 Hyper text transfer protocol
ftp 21 File Transfer Protocol
https 443 Hypertext transfer protocol
secured
ssh 22 Secure Shell
sftp 22 (Encrypted Data) Secure File
Transfer Protocol
smtp 25 Simple Mail Transport Protocol
telnet 23 (a simple, text-based network
protocol that is used for
accessing remote computers
over TCP/IP networks like the
Internet.)
rlogin 513 (Like SSH) a tool for remotely
using a computer over a
network. Like Putty
DNS *53 (Named Route 53 in AWS) Domain
Name Server
RDP 3389 Remote Desktop Protocol.
(Enables Remote Desktop
Connection)

125
Q

WHAT IS THE DIFFERENCE BETWEEN TCP AND UDP?

A

WHAT IS THE DIFFERENCE BETWEEN TCP AND UDP?

  1. Transmits Critical Data - TCP (Transmission Control Protocol)(TCP)
  2. Broadcasts ( sends signal to all systems in network) non- critical data eg DHCP request (needs broadcast) - UDP (User Data Gram Protocol)(UDG)
  3. It is reliable and will guarantee transmission of data from sending to receiving system TCP
  4. It is not reliable and will not guarantee Data transmission from sending system to receiving system UDP
  5. Slower at transmitting Data than UDP. TCP is slower due to a lot of overhead mechanisms such as 3 Way Handshake, Error detection and Correction (CRC), and Flow control mechanism (windowing)
  6. UDP - Faster at Transmitting Data than TCP
  7. It is a connection oriented protocol and hence performs a 3 way handshake between the sending and the receiving systems before data transmission TCP
  8. It is a connection less oriented protocol and does not perform a 3 way hand shake before data transmission UDP
  9. TCP comes with a built in error detection and correction mechanism called CRC ( Cyclic Redundancy Check)
  10. UDP has no built in detection and correction mechanism
  11. TCP comes with a built in flow control mechanism called “Windowing”
  12. Comes without a flow control Mechanism
  13. Able to retransmit data (get all of it or you will not get anything)
  14. Not able to retransmit data (like a radio broadcast)
  15. Work at the Transport Layer - TCP
  16. Work at the Transport Layer - UDP
126
Q

What is a 3 Way Hand Shake?

A

Three Way Handshake
3 Way handshake occurs before a session is established (link established between 2 systems)

When 2 systems are about to talk to each other using TCP.
1. The sending system sends a SYN signal to the receiving system
2. Receiving System sends a response with an ACK/SYN signal to the sending signal
3. Then sending system sends an ACK (acknowledgement) to the receiving System
before sending data

If a 3 way handshake is not successful then TCP data is not sent

ACK - Acknowledgement
SYN – Signal?

  1. Sending Signal sends signal to receiving system saying “are you there” – SYN signal
  2. Receiving System responds to the Sending system saying “I am there”- ACK/SYN Package (Acknowledgement)
  3. Sending system sends signal to receiving system saying “ok I am sending data now” - ACK
127
Q

What is CRC?

A

CRC(Cyclic Redundancy Check): - It is an error detection and correction mechanism of TCP

CRC check means it counts the packets in the segment and tallies it and labels it and once it gets to the receiving system (the TCP in receiving system will verify if all packets were received or matches CRC tally by performing another TCP check). If it matches, it will send it forward. If it does not match, it will not send it forward to the application layer but requests a resend from sending TCP. TCP will never send partial information. It has to be 100% or TCP will never send it. If it fails for a while it will stop sending.

128
Q

What is Windowing?

A

Windowing is the flow control mechanism that comes with TCP. It regulates data flow in TCP.

Will not send a window until it is done with 1st window.

129
Q

Describe TCP Segments and IP Packets

A

TCP is protocol for Transport layer which uses segments (Segments are full of data in the form of IP packets (data carriers) that have the data).

TCP will bundle it in segments and sends it across to receiving system

130
Q

List some TCP operations?

A

TCP operations: - map drive, network,

131
Q

UDP additional notes

A

UDP is used for hacking by sending a fake broadcast that overwhelms the network leading to a Denial of service attack

132
Q

What is a correction oriented protocol?

A

Connection Oriented

Sending System must send a message and receive response from the receiving system before data is transported

WINDOWS: SYSTEM ADMIN (12 decks)

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