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Ch. 21: Local Area Network
Terms in this set (141)
A Ethernet frame holds a maximum of ____________ bytes.
What is Network protocol?
Takes info from NIC card, organizes it, and sends it to an application that needs it. Then, takes outgoing data from the application and hands it to the NIC to be sent out over the network.
- What are protocol stacks?
A group of protocols.
What is the Transmission Control Protocol/Internet Protocol (TCP/IP)?
The primary protocol of most modern networks, including the Internet.
- What are the two pieces of information a network must provide?
It has to uniquely identify the machine, and it must locate that machine within the larger network.
What is an IP address?
Identifies the PC and the network where it resides.
Parts of an IP address include:
- The network ID portion identifies the network.
- The host ID, or host part identifies the local computer on the network.
What is the Internet Protocol version 4 (IPv4)?
The primary addressing scheme of today. Consist of four sets of eight binary numbers (octets), each set separated by a period.
What is a subnet mask?
A value used by the NIC that distinguishes which part of the IP address identifies the network ID and which part of the address identifies the host.
It blocks out (or masks) the network portion of an IP address.
Every computer on a single LAN must have the same _______ ________ and a unique ________ ________.
network ID, host ID
Every computer on the network must have a unique __________________.
What is an IP conflict?
When two computers aren't able to connect to each other due to sharing the same IP address, causing other computers to not know where to send data.
An IP address can never end with a ____ or a _______.
What is a Class C address?
Has a subnet mask of 255.255.255.0
What is a Class B address?
Has a subnet mask of 255.255.0.0
What is a Class A address?
Has a subnet mask of 255.0.0.0
What is Classless Inter-Domain Routing (CIDR)?
Current system for creating and notating subnets. Refers to the subnet mask by the number of ones it contains.
ex: 11111111.11111111.11110000.00000000 = /20 network ID = 255.255.240.0
What is a router?
A device that has at least two IP addresses: one that connects to your LAN's switch and one that connects to the "next network".
What is a default gateway?
The IP address of the "LAN" side of your router, which is the address your computer uses to send data to anything outside your network ID.
What is a Domain Name Service (DNS)?
Special computers that keep databases of IP addresses and their corresponding names.
ex: IP address 209.34.420.163 = www.totalsem.com
(-) What are the seven domain name qualifiers (top-level domains/TLDs)?
- .com (general business)
- .edu (educational organizations)
- .mil (military organizations)
- .int (international)
- .org (nonprofit organizations)
- .gov (government organizations)
- .net (internet organizations)
(***) When you're configuring a computer to connect to a network, you must enter:
the IP address, the subnet mask, the default gateway, and at least one DNS server.
When do you neeed to set up
A network printer
What is the Dynamic Host Control Protocol (DHCP)?
Protocol that enables client hosts to request and receive TCP/IP settings automatically from an appropriately configured server.
What is a static IP address?
An IP address that doesn't change until it's changed manually.
When you want to be positive that the data moving between two systems gets there in good order use a ____________________ application.
connection-oriented/Transmission Control Protocol (TCP)
used to bank transactions
If it's not a big deal for data to miss a bit or two while moving between systems, ______________________application is the way to go.
connectionless/ User Datagram Protocol (UPD)
used for voice-over id
Most TCP/IP applications use TCP instead of UDP.
What is the Transmission Control Protocol?
The connection-oriented protocol used with TCP/IP
What is the User Datagram Protocol?
The connection-less protocol used with TCP/IP
TCP is best used when:
Communication rules require both the sending and receiving machines to acknowledge the other's presence and readiness to send and receive data.
UDP is best used when:
you have a lot of data to send that doesn't need to be perfect
Over ______ percent of all TCP/IP applications use TCP.
When does UDP work best?
When you have a lot of data to send that doesn't need to be perfect or when the systems are so close to each other that the chances of a problem occurring are small
What are TCP/IP services?
Services such as HTTP or SSH that run atop TCP/IP.
What does SSH allow you to do?
Allows you to access a remote systems's terminal as though you were actually in front of that machine.
The goal of TCP/IP is:
to link any two hosts whether the two computers are on the same LAN or on some other network within the WAN.
Where do you go to configure TCP/IP network settings in Windows?
Right-click on Network | Select properties, or open Control panel | Network and Sharing center
(start notes here) What are the tools used to test and configure TCP/IP?
And how do you access them?
Ping, ipconfig, ifconfig, nslookup, tracert, and traceroute.
Open a command prompt to run them.
What is the ping command?
Used to verify if a computer can talk to another.
What is the -t switch in ping?
Allows ping to continuously send ping packets until stopped with a break command (ctrl-c).
What is the -l switch in ping?
Enables you to specify how big a ping packet to send.
ping switches- (t, l, and n)
What is the ipconfig command?
In Windows. Allows you to check your network settings.
Type "__________________" to see your TCP/IP settings.
What is the ifconfig command?
Similar to the ipconfig command in Windows. Used in Mac OS X and Linux with no switches applied.
(-) Typing ipconfig /renew will get you __________________________, while ipconfig /release will _______________________________.
a new IP address, give up the IP address you currently have.
What is the nslookup command?
Enables you to determine exactly what information the DNS server is giving you about a specific host name.
Type nslookup from the command prompt and press the ENTER key.
What is the tracert command?
Shows the route that a packet takes to get to its destination.
From a command line, type tracert followed by a space and an IP address or URL.
What is traceroute?
Mac OS X/Linux equivalent of tracert.
What does the output of a tracert/traceroute command show?
The route from your machine to the destination machine, including all devices the packet passes through and how long each hop between devices takes.
How to configure TCP/IP to receive an IP address manually
Control Panel | Network and sharing center | change adapter setting, highlight IPv4, click properties
What is Automatic Private IP Addressing (APIPA)?
Feature that automatically assigns an IP address to the system when the client cannot obtain an IP address automatically.
(***) The Internet Assigned Numbers Authority has set aside the range of addresses from _____________ to _______________ for this purpose (the APIPA range).
The 32-bit IPv4 standard offered only ________________ addresses.
What is the Internet Protocol version 6 (IPv6) scheme?
Expands the 32-bit IP address space to 128 bits, allowing up to 2(128) addresses.
What are the differences between IPv4 and IPv6?
IPv6 uses a colon instead of a period like IPv4. Also, each IPv6 address has eight groups of four hexadecimal characters.
Each group is a hexadecimal number between 0000 and FFFF called (unofficially) a field or hextet.
Where do IPv4 addresses come from?
Either the IP address is typed in (static IP addressing), or you use DHCP (dynamic IP addressing)
How does IPv6 addressing work differently than IPv4?
Instead of one IP address, you can have multiple IP addresses on a single network card (usually up to three).
(***) Shorthanding an IPv6 address:
Double-colon can only be used once, leading 0's can be removed, and 0's after a colon can only keep one/leading 0.
IPv6 still uses subnets.
IPv6 uses the "/x" Classless Inter-Domain Routing (CIDR) nomenclature.
The /x refers to the number of bits in the subnet mask.
The last 64 bits of an IPv6 address are generated randomly or using the MAC address, leaving a maximum of 64 bits for the network ID. Therefore, no subnet is ever longer than /64.
What is a link-local address?
IPv6 address a computer gives itself when it first boots. IPv6's equivalent to IPv4's APIPA address.
The first 64-bits of a link-local address are always __________.
What are the two choices between operating systems on how to make the last 64 bits of an IPv6 address?
Windows makes a random value that is unique and never changes.
Linux and Mac OS X build the value from the MAC address of the network card (called the Extended Unique Identifier, 64-bit, or EUI-64).
What is a global address?
A second IPv6 address that allows a computer to access the internet.
* the first 64 bits of a
What is the process to get a global address?
1. An IPv6-capable computer boots up and sends out a router solicitation message
2. An IPv6-configured router hears the request and then sends to the computer a router advertisement containing the prefix and DNS.
3. The computer takes the prefix and adds the EUI-64 or a random value to the end of the prefix.
ex: If the MAC address is 00-0C-29-53-45-CA, then the address is 20C:29FF:FE53:45CA.
4. Putting the prefix with the last half of the address, you get the global address: 2001:470:ABCD:1:20C: 29FF:FE53:45CA
What needs to be in place in order to have network connectivity?
- Connected NIC: the physical hardware that connects the computer system to the network media.
- Properly configured TCP/IP: Your device needs correct TCP/IP setting for your network
- Network client: The interface that allows the computer system to speak to the protocol
NICs are manufactured to -
operate on specific media and network types, such as 1000BaseT Ethernet.
What is full-duplex mode?
When a NIC is able to send and receive data at the same time.
What is autosensing?
A feature used by NICs and switches to accommodate very old devices that might attach to the network and need to run in half-duplex mode.
What is half-duplex mode?
When a NIC can send and receive, but not at the same time.
Modern NICs contain a LED status indicator known as a ____________________ that gives information about the state of the NIC's link to the other end of the connection.
Link lights are the first thing you check when -
you think a system is disconnected from the network.
A properly functioning link light is ____________ on when the NIC is connected to another device.
What is the activity light?
Turns on when the NIC detects network traffic. Makes an intermittent flickering when working properly.
What is a popular feature of most NICs?
The ability to turn on or wake up a powered-down PC (Wake-on-LAN).
What do these LED readings mean:
- solid green light
- flashing green light
- no green light
- flashing amber light
- intermittent connectivity
- no connectivity
- collisions on the network (might not be a problem)
What is Wake-on-LAN?
Useful when you want to wake up one or multiple computers that you aren't physically near.
To wake up a PC using Wake-on-LAN, you need:
- a second PC to send a special pattern
- a magic packet (a broadcast packet that essentially repeats the destination MAC address many times)
What is the downside to Wake-on-LAN?
It can turn on/wake up laptops using a wireless connection, even if they aren't plugged in or in use (such as laptop in a carrying case)
Has to be enabled within the ______________________ tab.
What is Quality of Service (QoS)?
Enables busy networks to prioritize traffic.
What are resources?
Files shared across your network, such as folders, printers, multi-function devices, and Internet connections.
Client for Microsoft Network
Default Network Client for Windows
When you share over a network, every OS uses specific network sharing permissions to -
allow or restrict access to shared resources.
On a non-NTFS volume like an optical media disc or a flash-media USB drive, you only have three levels of permission:
Read, Read/Write, and Owner
Microsoft uses NTFS for authorization for both local users and network users, which means -
you use the network share to actually share the resource, but use NTFS to say what users can do with the resource.
A shared folder on an NTFS drive must have __________ the network permissions and the NTFS permissions set to let others access shared resources
Windows and other operating system networks work in one of three categories:
What is a workgroup?
A simple, decentralized network that Windows PCs are configured to use by default.
Workgroups lack centralized control over a network, which means -
all systems connected to the network are equals.
Where are usernames and passwords stored?
In an encrypted format on your computer.
How do you share a folder?
Right-click on the folder and select "Share with | Specific people"; this opens the File Sharing dialog box.
You may give an account ___________________ permissions, while the person who created the folder is assigned as _________________.
What's the read permission?
You can see/open files in the folder, but can't save anything into the folder.
What's the read/write permission?
Same as read, but you can save files into a folder.
What is the owner permission?
Same as read/write, but you can also set the permissions for other users on the folder.
What are the three choices one can use to protect user names and passwords?
1. You can make people log on to shares.
2. You can create the same accounts (same username and password) on all the computers and give sharing permissions to all the users for all the shares.
3. You can use one account on all computers
What are domains?
Large networks with a specific server to control access to the network's resources.
What would you need in order to use a domain on a network of Windows computers?
A computer running Windows Server.
An administrator creates a domain on the Windows Server system, making it the _____________________.
domain controller (DC)
New accounts created by the administrator on the domain controller are called _______________________.
* You can manage a domain from the command-line with the _____________________ command.
The domain controller authenticates a user when that user logs into a domain computer. This also makes it a ______________________________.
What is the best feature of using a domain?
You can log on to any computer on the domain using the same domain account. This is known as single sign-on.
What's the downside to using a domain?
They require special servers and lots of administration, despite providing lots of security and single sign-on.
What are the downsides to using workgroups?
They provide no security and require lots of signing on to access resources.
How do you create a homegroup?
Open the HomeGroup Control Panel applet.
What is a homegroup?
A windows feature that connects a group of computers using a common password - no special user names required. Allows people to share files, not folders.
Available in Windows 7 and later
Homegroups share ______________, not __________________ by default.
What are the four sharing options within a homegroup?
Nobody (item is not shared), Homegroup (read), Homgroup (read/write) and Specific people.
What are the two ways to look at connectivity issues?
When your computer loses physical connectivity, and when you're on the network and can't access a particular resource.
What does a red X over the network icon in the notification area indicate?
You're not connected to the network.
What steps should you take when you suffer loss of connectivity (red X)?
First, check if the cable is unplugged at your system or the wall outlet.
Then check if the NIC is disabled in Device Manager. Is the cable connected to the switch?
Which errors should you look for that point to physical disconnection.
- A "No server is found" error.
- No systems seen other than own in the system's network explorer utility
- Multiple systems failing to access the network
If you suspect a hardware issues, what should you check first?
the lights on the NIC and switch
If the lights on the NIC and switch aren't lit, that means ____________________________.
the cable isn't connected somewhere.
How do you eliminate the possibility of a failed switch or larger problem?
Check to see that other people can access the network, and that other systems can access the shared resource (server) that the problem system can't see.
In order to check an outlet, you should:
plug the system into a known good outlet. If it connects with the second outlet, suspect something is wrong with the cable running from the first outlet.
A bad ___________ can also generate a "can't see the network" problem. If this happens, you should ______________________________________.
NIC, run the diagnostic software if available to check the NIC's circuitry.
What is a loopback test?
Sends the data out of the NIC and checks to see if it comes back.
What is a loopback plug?
A plug inserted into the NIC's port to achieve an external loopback.
What is a time-domain reflectometer (TDR) tester?
It's used to measure impedance in network cabling.
When you're testing a cable run, always include the ____________________ as you test.
What is a tone generator?
Connects to a cable using alligator clips, tiny hooks, or a network jack.
It sends an electrical signal along the wire at a certain frequency.
What is a toner?
The generic term for two separate devices that are used together: a tone generator and a tone probe.
Also known as "Fox and Hound"
What is a tone probe?
Emits a sound when it is placed near a cable connected to the tone generator.
When failing to connect to a new resource, what should you do if you're not sure you have the right share name?
Go check at the serving system.
When failing to connect to a new resource, what should you do if you don't have the required user name/password?
Ask someone who might know, or double-check that your account has access.
When failing to connect to a new resource, what should you do if you don't have permission to use/access/connect to the shared resource?
Make sure you have the correct permissions.
When failing to connect to a new resource, what should you do if you're not on the right homegroup/domain/workgroup?
Check your system and the sharing system to verify which workgroup/domain name to use. On a homegroup, make sure you used the right password.
When failing to connect to a new resource, what should you do if the folder or printer isn't shared?
When failing to connect to a new resource, what should you do if the folder or printer doesn't exist?
Make sure the serving system still hosts the folder you want. Install the network printer if you haven't yet.
If you can't connect to a resource you've used many times before, you should:
- Check that the resource is visible using Network
- Check that the serving system is on
- Check that the computer is physically connected to the serving system.
What is the net command?
Allows users to view a network without knowing the names of the other computers on that network.
In order to use the net command, type _________ into the command prompt and press enter.
What happens when the net command is run?
Net view returns a lsit of Windows computers on the network.
What is the nbtstat?
Stands for NetBIOS over TCP/IP Statistics.
THIS SET IS OFTEN IN FOLDERS WITH...
Ch. 17: Troubleshooting Operating Systems **
Ch. 16: Working with the Command-Line Interface
Ch. 4: Microprocessors ***
Ch. 18: Virtualization
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