Download Review For Exam 2

Review For Exam 2
(Week 8, Wednesday 3/1/2006)
© Abdou Illia, Spring 2006
1
IP Subnetting
2
Structure of IP addresses
Network Part (n)
Local Part (h)
Sgmt. part Host part
Class A
nnnnnnnn.hhhhhhhh.hhhhhhhh.hhhhhhhh
10.0.0.1 – 126.255.255.255
Class B
nnnnnnnn.nnnnnnnn.hhhhhhhh.hhhhhhhh
128.0.0.1 – 191.255.255.255
Class C
nnnnnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh
192.0.0.1 – 223.255.255.255
3
Reserved IP addresses
IP addresses reserved for private use.
Class
Range
A
10.0.0.0 – 10.255.255.255
B
172.16.0.0 – 172.31.255.255
C
192.168.0.0 – 192.168.255.255
Special IP addresses.
Address
Use
255.255.255.255
Example: 10.255.255.255
Local broadcast to LAN computers
Broadcast to network 10.0.0.0/8
127.0.0.1
Loopback address (for self addressing)
0.0.0.0
Prohibited
169.254.x.x
Automatic Private IP Addressing
4
Structure of IP addresses
Network Part

Segment
Part
Host
Part
The division between Network part,
Segment part, and Host part is determined
by a computer or a router by using a
network mask.
5
Network mask

A 32 bit number, just like an IP address,
where all bits in the Network Part and the
Segment Part are set to 1, and all bits in
the Host Part are set to 0. Example:
11111111 11111111 11111111 00000000
(or 255.255.255.0 in decimal notation)

Computers use Network mask, along with
the IP address, to determine whether or
not a destination IP address is on the
same logical network.
6
The ADDing technique

Do the following three Class C IP addresses
belong to the same network? 192.168.1.1,
192.168.1.50 and 192.168.2.1
128
64
32
16
8
4
2
1
IP:
11000000
10101000
00000001
00000001
192.168.1.1
Mask:
11111111
11111111
11111111
00000000
255.255.255.0
Network:
11000000
10101000
00000001
00000000
192.168.1.0/24
IP:
11000000
10101000
00000001
00110010
192.168.1.50
Mask:
11111111
11111111
11111111
00000000
255.255.255.0
Network:
11000000
10101000
00000001
00000000
192.168.1.0/24
IP:
11000000
10101000
00000010
00000001
192.168.2.1
Mask:
11111111
11111111
11111111
00000000
255.255.255.0
Network:
11000000
10101000
00000010
00000000
192.168.2.0/24
Network 1: 192.168.1.0/24, i.e network starting at 192.168.1.0 with network mask 255.255.255.0.
Network 2: 192.168.2.0/24, i.e network starting at 192.168.2.0 with network mask 255.255.255.0.
7
Two Virtual LANs
192.168.2.1
255.255.255.0
192.168.1.1
255.255.255.0
192.168.1.2
255.255.255.0
192.168.1.3
255.255.255.0
192.168.2.2
255.255.255.0
Switch
192.168.2.3
255.255.255.0
8
Two interconnected LANs
9
Subnetting a class C network



Suppose the 192.168.1.0/24 network
You want to divide that network into two segments
You can decide to use the first bit of the fourth octet as
dividing point between your network segments. So, your
network mask would be:
128
64
32
16
8
4
2
1
11111111 11111111 11111111 10000000
And you will have about 27 = 128 hosts in each
segment.
Segment 1: 192.168.1.0 to 192.168.1.127 Segment 2: 192.168.1.128 to 192.168.1.255
How to create the two segments
using the ADDing technique?
10
128
64
32
16
8
4
2
1
Subnetting a class C network
Segment 1: 192.168.1.0 to 192.168.1.127
IP:
11000000
10101000
00000001
00000001
192.168.1.1
Mask:
11111111
11111111
11111111
10000000
255.255.255.128
Network:
11000000
10101000
00000001
00000000
192.168.1.0/25
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IP:
11000000
10101000
00000001
01111111
192.168.1.127
Mask:
11111111
11111111
11111111
10000000
255.255.255.128
Network:
11000000
10101000
00000001
00000000
192.168.1.0/25
11
Subnetting a class C network
Segment 2: 192.168.1.128 to 192.168.1.255
128
64
32
16
8
4
2
1
IP:
11000000
10101000
00000001
10000000
192.168.1.128
Mask:
11111111
11111111
11111111
10000000
255.255.255.128
Network:
11000000
10101000
00000001
10000000
192.168.1.128/25
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IP:
11000000
10101000
00000001
11111110
192.168.1.254
Mask:
11111111
11111111
11111111
10000000
255.255.255.128
Network:
11000000
10101000
00000001
10000000
192.168.1.128/25
12
Question 1


Network A is IP network 192.168.2.0/24 (i.e a
Class C network with a default 24-bit mask).
Using the IP Subnet Calculator, determine the
maximum number of hosts (computers) in
each of the Network A’s subnets assuming
that there are two subnets. You answer:
________.
Using the IP Subnet Calculator, determine the
maximum number of subnets for a Class B
network assuming that the four first bits of the
third octet in each IP address are used as
subnet bits. Your answer: _____. What is the
maximum number of computers for each
subnet? Your answer: ______.
13
Question 2

Consider the 192.168.2.0/24 network.


Suppose that the 192.168.2.0/24 network is
segmented, and became 192.168.2.0/25



What is the maximum number of hosts in that network?
What is the maximum number of hosts in in each subnet?
Would IP address 192.168.2.1 be in the same subnet as
IP address 192.168.2.126?
Consider the 192.168.2.0/24 network. You
want to segment that network in order to
create 4 subnets.


What would be the four (4) address ranges?
What would your subnet mask be?
14
Disk Management
15
Basic disk


A physical disk that can be accessed by MS-DOS and all Windows-based operating
systems.
Basic disks can contain up to 4 primary partitions, or 3 primary partitions and an
extended partition with multiple logical drives.
Primary
partition
1
Primary
partition
2
Primary
partition
3
Primary
partition
4
Primary
partition
1
Primary
partition
2
Primary
partition
3
Extended
partition
• A primary partition is a portion of a physical disk that functions as
though it were a physically separate disk.
• A special kind of partition used to create one or
more logical drives
• You create a primary partition, then you format it with a file system
(FAT or NTFS,) and then assign a drive letter to it (e.g. C:, D:, F:, etc.)
• After you create a logical drive, you format it and
assign it a drive letter (e.g. G:, H:, etc.)
• A primary partition can start the OS (contain the boot files)
• An extended partition cannot start the OS.
Note: With GPT (GUID partition table) disk-partitioning scheme that is used by the Extensible Firmware
16
Interface (EFI) in Itanium-based computers, we can create up to 128 (primary) partitions per disk
Dynamic disk


With Win 2000, you can convert a Basic disk to a Dynamic disk
With a dynamic disk, you can create an unlimited number of volumes
Volume
C:

Volume
D:
Volume
E:
Etc….
Configuration
partition (1 MB)
Dynamic disks provide features that basic disks do not, such as:
Special partition
automatically
created to store
the configuration
of the disk

the ability to create volumes that span multiple disks (spanned and striped
volumes), and
 the ability to create fault tolerant volumes (mirrored and RAID-5 volumes).


A spanned volume is a dynamic volume consisting of disk space on more
than one physical disk. Spanned volumes are not fault tolerant and cannot be
mirrored.
A striped volume is a dynamic volume that stores data in stripes on two or
more physical disks. Striped volumes do not provide fault tolerance. If a disk in
a striped volume fails, the data in the entire volume is lost.
17
Mirrored volume



A fault-tolerant volume that duplicates data on two physical disks
If one of the physical disks fails, the data on the failed disk becomes unavailable, but the
system continues to operate.
You can create mirrored volumes only on dynamic disks.
file1
file2
file3
file4
file1
file2
file3
file4
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RAID-5 volume




A fault-tolerant volume with data and parity striped intermittently across three
or more physical disks.
Parity is a calculated value that is used to reconstruct data after a failure
If a portion of a physical disk fails, Windows recreates the data that was on the
failed portion from the remaining data and parity.
You can create RAID-5 volumes only on dynamic disks,
Disk 1
Parity
Data
Data
Data
Data
Disk 2
Data
Parity
Data
Data
Data
Disk 3
Data
Data
Parity
Data
Data
Disk 4
Data
Data
Data
Parity
Data
Disk 5
Data
Data
Data
Data
Parity
19
Converting Basic disk
to Dynamic disk

For the conversion to succeed:



Once converted:



any disks to be converted must contain at least 1 MB of space for
the dynamic disk database.
Note: Windows 2000 automatically reserve this space when
creating partitions or volumes on a disk (This space may exist even
if it is not visible in Disk Management.)
a dynamic disk will not contain primary partitions or logical drives
a dynamic disk cannot be accessed by MS-DOS, Windows 95,
Windows 98, Windows Millennium Edition, Windows NT, or
Windows XP Home Edition
When you convert a basic disk to a dynamic disk:

any existing partitions or logical drives on the basic disk become
simple volumes on the dynamic disk.
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Converting Dynamic disk to Basic
disk

The disk must be empty before you can change it back to
a basic disk

Converting a Dynamic disk to Basic disk causes all data to
be lost

If you want to keep your data, back it up or move it to
another storage device

You must remove all volumes from the dynamic disk
21
Limitations of Dynamic disk

Dynamic disks are not supported on:
 Portable computers
 Removable disks
 Detachable disks that
use Universal Serial Bus (USB)
or IEEE 1394 (also called FireWire) interfaces,
 Disks connected to shared SCSI buses

Dynamic volumes (and the data they contain)
cannot be accessed by, or created on:
 Computers
running MS-DOS, Windows 95,
Windows 98, Windows Millennium Edition, Windows NT
4.0, or Windows XP Home Edition
22
File system security
23
Shared Folders
Requirements for creating a shared folder:





Any supported File system (FAT, NTFS)
If server in a domain, you must be Administrator or Server Operator
If server in a workgroup, you must be Administrator or Power user
If Client computer running a Workstation OS, you must be Administrator or
Power user
Note: Users that are granted the Create Permanent Shared Objects right can
also create shared folders on the computer where the right is assigned
To see all shared folders on a computer:
1)
2)
3)
Click Start. Then click Run
Type \\ComputerName (where
ComputerName is a valid network computer
name like SRVDC18)
Click OK.
OR
1)
2)
3)
Open Computer Management
In the console tree, double-click Shared
Folders
Click Shares
To share a folder on a computer:
1)
2)
3)
4)
5)
6)
7)
Open My Computer (Right-click/Open)
Select a disk, then the folder to share
Right-click the selected folder
Click Properties
Click the Sharing tab
Check Share this folder
Click Apply, and then OK.
24
Shared Folder Permissions



Multiple Permissions (The Combination Rule)

If a user is assigned a permission for a Shared folder and

If the use user belongs to a group to which a different permission is
assigned,

Then the user’s effective permissions are the combination of the user
and group permissions
Deny overrides Allow

If you deny a shared folder permission to a user and

If you allow the same permission to a group the user belongs to

Then the user will not have that permission.
Copying or Moving Shared folders

If you copy a Shared folder, the original folder is shared but not the copy

If you move a Shared folder, it is no longer shared.
25
NTFS Permissions

Multiple Permissions

NTFS file permissions take priority over NTFS folder permissions




A user can always access files for which he/she has permissions using UNC.
E.g. \\SRVDC16\Data\file1.txt
Denying a permission for a user blocks that permission, even if the
permission is granted to a group the user belongs to.
Permission Inheritance

By default, permissions assigned for the parent folder are inherited at
subfolder and file level

To prevent automatic inheritance, explicit permissions assignments must
be done at subfolder and/or file levels.
Copying or Moving Files and Folders

When a file/folder is moved within an NTFS partition, it retains its permissions

When a file/folder is copied to another NTFS partition, it inherits the
permissions of the destination folder (Golden rule)

When a file/folder is copied to a FAT partition, it loses its NTFS permissions
26
Shares & permissions
Sharing
Setting
folders/files permissions
FAT
NTFS
FAT
NTFS
Folders/Subfolders
YES
YES
YES (but
limited)
YES
Files
NO
NO
NO
YES
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Exercise 1

You shared a folder on a Windows 2000 Server
computer for users in your company’s London
office. You place several subfolders in the London
Folder as shown in the exhibit.
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Exercise 1 (Cont.)

The Marketing-2 folder is compressed. You want to
delete Marketing-2, but you want to keep all the files
that are currently in the folder. You plan to copy all the
files in Marketting-2 into the Marketing folder before
deleting Marketing-2. You want these files to remain
compressed. However, you do not want to compress
any existing files in Marketing or compress any other
new files added to the Marketing.
What should you do before you delete Marketing-2?
A. Copy all the files from Marketing-2 to Marketing.
B. Move all the files from Marketing-2 to Marketing.
C. Compress Marketing and then copy all the files from Marketing-2 to Marketing.
D. Compress Marketing and then move all the files from Marketing-2 to Marketing.
29
Distributed File System, Disk
Quotas
30
Dfs: Scenario 1
Dfs not used
Server 1
Server 2
 Four shared folders on 4 different servers
 User need to know servers and folders
names to access resources
 User need to connect to each server
\Install
\Data
Server 3
Server 4
\Policy

\Sales
Problems if there are dozens of servers
31
Dfs: Scenario 2
Server 1
Using Dfs
Server4
 Have a server with Dfs and Dfs links
created
 User need to connect to a single server
 User doesn’t need to know servers and
folders names
Dfs server
Link to Install
Link to Policy
Link to Data
Link to Sales
\Install
\Policy
Server 2
Server 3
\Data
\Sales
32
Dfs implementation in Win 2000
There are two Dfs models:
 Standalone Dfs
 Created on standalone servers (Workgroup)
 Doesn’t take advantage of the Active Directory
 Offer a single level of Dfs links

Domain-Based Dfs
 Created
on a Domain controller or Member
server (in a Domain)
 Uses Active Directory
 Offer a deep hierarchy Dfs links
33
Dfs implementation in Win 2000
Only 1 Dfs root per server is allowed
 Dfs can be created on FAT or NTFS
partitions
 To create a standalone Dfs root, use the
Distributed File System snap-in

34
Disk Quotas

Disk Quotas needed because
 Many
users save data on shared folders
 Users must be prevented from filling disk
capacity

Disk Quotas options
 Enable
Disk quotas w/o limiting disk usage
 Set a default quota for all users
 Determine quotas on per-user basis
Disk quotas are determined based on the uncompressed files/folders sizes
35
Taking ownership
1) Disk quotas are based on files/folders ownership
2) If you have the Take ownership permission on a file/folder, you can take its
ownership.
36