Networking Guide
Chapter 3, Administering TCP/IP
Creating subnets
Creating subnets
In TCP/IP, the DARPA Internet support
includes the concept of the subnet, sometimes called a subnetwork.
This is a mechanism
that enables several local networks to appear as a single Internet
network to off-site hosts. You should consider using subnets in
the following instances:
-
When you want to hide the local network topology to the outside
world. Using subnets requires only a single route to external gateways.
-
When you want the ability to administer IP addresses locally.
For example, a company may have an engineering subnet, a product marketing
subnet, and a sales subnet, each administered by a different administrator
who has control of IP addresses in a given range.
-
When network bandwidth is limited due to cabling constraints. Setting up
subnets, each separated by a gateway host, limits local subnet
packets to those that are either destined for or sent from a local host.
In this way, the overall network traffic each host on the subnet sees
is lessened.
Setting up a subnet consists of:
-
determining the appropriate IP addresses for your subnets.
-
configuring subnet hosts with the correct IP addresses and netmasks.
-
configuring gateway hosts between subnets.
To set up subnet addresses, you must use a segment of the
host portion of the IP address to use as the subnet address.
For example, consider the following IP addresses and netmasks:
For class A and B networks, you can create subnets by converting the
second and third octets, respectively, from host addresses to subnet
addresses. Notice how the netmask changes accordingly:
The class A network 16 can now have up to 254 subnets
(16.1 - 16.254).
The class B network 132.147 can also have up to 254
subnets (132.147.1 - 132.147.254). While the netmask
masks the network portion of the address, the broadcast address
exposes the network
address and hides the host portion. For example, the broadcast address for
the subnet 132.147.246, with a netmask of
255.255.255.0, is 132.147.246.255.
NOTE:
The subnet portion of the network address cannot consist
of all binary zeros (0) or ones (255). See RFC 950 for
more information.
For more information on setting netmask and broadcast addresses, see
Appendix A, ``Configuration parameters'' in Configuring Network Connections.
Partitioning a class C address is slightly more complex, as you must
take a portion of the fourth octet as the subnetwork. For example,
you might partition the first three (high order) bits of the fourth
octet to represent the subnetwork, with the last five bits representing
the host:
This scheme allows for up to 6 subnets of 30 hosts each, for a total of
180 hosts. The netmask for the hosts on these subnets is
255.255.255.224; 224 is a decimal representation
of the binary octet 11100000, which masks
the subnet portion of the IP address.
Possible subnets for the class C
network 221.138.62.0, with associated broadcast addresses, are:
----------------------------------------------------
Subnet Hosts Broadcast address
----------------------------------------------------
221.138.62.32 .33-.62 221.138.62.63
221.138.62.64 .65-.94 221.138.62.95
221.138.62.96 .97-.126 221.138.62.127
221.138.62.128 .129-.158 221.138.62.159
221.138.62.160 .161-.190 221.138.62.191
221.138.62.192 .193-.222 221.138.62.223
After you determine the new addresses for your hosts, you must
configure them with the
Network Configuration Manager
or by
editing /etc/tcp.
In addition, you must
configure gateways
between your subnets: these are hosts with multiple networking cards
that serve more than one network.
|
Networking
guide
Call
: 800-519-
2267
MCSE
Boot Camp,
MCSE
Certification
boot
camp,
MCSE
Training
boot
camps,
MCSE
certification
boot
camp
training at
California and
Maryland
USA. Also
CCNA,
CCNP,
CISSP,
Red Hat
Linux
Certification
notes.
Vibrant
boot camp
offers MCSE,
CCNA,
CCNP Certification back to back
Vibrant
offers
MCSE
certification
training
boot camp
for $5400
all inclusive,
instructor
led at
California
and
Baltimore.
Vibrant
Bootcamp
Participants
come
from
All
Around
the
World.
Vibrant
has
trained
students
from
more
than
15
countries
like
USA,
UK,
(Scotland,
Ireland,
Wales),
Switzerland,
Germany,
Australia,
Canada,
France,
Holland,
Japan,
Belgium,
Bahrain,
New
Zealand,
Tanzania,
Turkey,
Kenya and
more. |
100BASE-X
100VG-AnyLAN
10BASE2
10BASE5
10BASE-FL
10BASE-T
Access Methods
Active Hubs
Additional
Administrative Tasks
Address Resolution
Protocol (ARP)
Addressing at the
Data Link Layer
Advantages of Packet
Switching
Analog Waveforms
AppleTalk
Assigning File-Level
Permissions on an NTFS Partition
Asynchronous Transfer
Mode (ATM)
Asynchronous
Transmission
Attenuation
Attenuation
Attenuation
Attenuation
Auditing
Backup
Band Usage (Baseband
or Broadband)
Bandwidth
Bandwidth
Bridges
Bridges
Brouters
Bus Topologies
Cable Media
Capacity
Capacity
Capacity
Centralized Computing
Characteristics of
Transmission Media
Choosing a RAID Level
Circuit Switching
Coax and Fire Code
Classifications
Coaxial Cable
Coaxial
Characteristics
Collaborative
Computing
Communications
Devices and OSI
Comparing Contention
and Token Passing
Configuring Network
Adapter Cards
Connection Services
Connection-oriented
and Connectionless Modes
Connectivity Devices
Connectors for
Coaxial Cable
Connectors for STP
Connectors for UTP
Contention
Controlling the Flow
of Data
Cost
Cost
Cost
Cost
Creating and
Assigning Permissions to a Shared Folder on Windows NT
Data Encryption
Data Link Control
(DLC)
Data Migration
Database Services
Datagram Packet
Switching
Defining a Network
Adapter Card
Delivering Packets
Demand Priority
Digital and Analog
Signaling
Disaster Recovery
Disk Duplexing
Distance Vector
Routing
Distributed Computing
Domain Name System
(DNS)
Electromagnetic
Interference
Electronic Mail
EMI Characteristics
EMI Characteristics
EMI Characteristics
EMI Characteristics
Error and Flow
Control at the Data Link Layer
Establishing
Troubleshooting Connectivity and Communication
Ethernet
Ethernet Cabling
Exercise 1.1: Logging
on as a Peer
Exercise 1.2: Windows
NT Access Permissions
Exercise 1.3:
Exploring the NT Workstation Service
Exercise 10.1:
Network Adapter Resource Settings
Exercise 10.2:
Windows NT Diagnostics
Exercise 11.1:
Mapping a Network Drive
Exercise 12.1: Using
Network Monitor
Exercise 12.2:
Creating a Chart in Performance Monitor
Exercise 12.3:
Performance Monitor Alerts, Logs, and Reports
Exercise 13.1: Modem
Troubleshooter
Exercise 13.2:
Windows NT Books Online
Exercise 2.1: Gateway
Services for NetWare
Exercise 2.2: SLIP
and PPP in Dial-Up Networking
Exercise 3.1:
Shopping for Network Cabling
Exercise 4.1:
Matching Topologies to Applications
Exercise 5.1:
Installing Network Protocols in Windows NT
Exercise 5.2: Network
Bindings
Exercise 6.1:
Enabling IPX Routing
Exercise 7.1:
Accessing an X.25 Network Through NT Dial-Up Networking
Exercise 8.1:
Creating a User Account in Windows NT
Exercise 8.2:
Creating Groups on Windows NT
Exercise 8.3: Sharing
a Directory on a Windows NT FAT Partition
Exercise 8.4: Setting
NTFS Permissions on a Shared Folder
Exercise 8.5: Sharing
a Directory Using Share-Level Security
Exercise 8.6: Sharing
a Directory Using User-Level Security
Exercise 8.7:
Creating a Local Printer with Windows NT
Exercise 8.8: Sharing
a Printer on the Network with Windows 95
Exercise 9.1:
Exploring Windows NTs Disk Administrator
Exercises
Exercises
Exercises
Exercises
Exercises
Exercises
Exercises
Exercises
Exercises
Exercises
Exercises
Exercises
Exercises
Extended LANs
(Wireless Bridging)
Fiber-Optic Cable
Fiber-Optic
Characteristics
Figure 1.1
Figure 1.10
Figure 1.2
Figure 1.3
Figure 1.4
Figure 1.5
Figure 1.6
Figure 1.7
Figure 1.8
Figure 1.9
Figure 10.1
Figure 10.2
Figure 10.3
Figure 10.4
Figure 10.5
Figure 10.6
Figure 10.7
Figure 10.8
Figure 11.1
Figure 11.2
Figure 12.1
Figure 12.10
Figure 12.11
Figure 12.2
Figure 12.3
Figure 12.4
Figure 12.5
Figure 12.6
Figure 12.7
Figure 12.8
Figure 12.9
Figure 13.1
Figure 13.2
Figure 2.1
Figure 2.10
Figure 2.11
Figure 2.12
Figure 2.13
Figure 2.14
Figure 2.15
Figure 2.16
Figure 2.17
Figure 2.2
Figure 2.3
Figure 2.4
Figure 2.5
Figure 2.6
Figure 2.7
Figure 2.8
Figure 2.9
Figure 3.1
Figure 3.10
Figure 3.11
Figure 3.12
Figure 3.13
Figure 3.14
Figure 3.15
Figure 3.16
Figure 3.17
Figure 3.18
Figure 3.19
Figure 3.2
Figure 3.20
Figure 3.3
Figure 3.4
Figure 3.5
Figure 3.6
Figure 3.7
Figure 3.8
Figure 3.9
Figure 4.1
Figure 4.10
Figure 4.11
Figure 4.12
Figure 4.13
Figure 4.14
Figure 4.15
Figure 4.16
Figure 4.17
Figure 4.2
Figure 4.3
Figure 4.4
Figure 4.5
Figure 4.6
Figure 4.7
Figure 4.8
Figure 4.9
Figure 5.1
Figure 5.10
Figure 5.11
Figure 5.2
Figure 5.3
Figure 5.4
Figure 5.5
Figure 5.6
Figure 5.7
Figure 5.8
Figure 5.9
Figure 6.1
Figure 6.10
Figure 6.11
Figure 6.12
Figure 6.13
Figure 6.14
Figure 6.15
Figure 6.2
Figure 6.3
Figure 6.4
Figure 6.5
Figure 6.6
Figure 6.7
Figure 6.8
Figure 6.9
Figure 7.1
Figure 7.10
Figure 7.11
Figure 7.12
Figure 7.13
Figure 7.14
Figure 7.15
Figure 7.16
Figure 7.2
Figure 7.3
Figure 7.4
Figure 7.6
Figure 7.7
Figure 7.8
Figure 7.9
Figure 8.1
Figure 8.10
Figure 8.11
Figure 8.12
Figure 8.2
Figure 8.3
Figure 8.4
Figure 8.5
Figure 8.6
Figure 8.7
Figure 8.8
Figure 8.9
Figure 9.1
Figure 9.2
Figure 9.3
Figure 9.4
Figure 9.5
Figure 9.6
Figure 9.7
File Archiving
File Services
File Storage
File Transfer
File Transfer
Protocol (FTP)
File-Update
Synchronization
Finding Resources on
Microsoft Networks
Frame Relay
Frequency-Division
Multiplexing
Gateway Services
Gateways
Getting Support
Global and Local
Groups
Groups
Groups
Groupware
Handling Broadcast
Storms
Handling Other
Network Problems
Hardware Access at
the Data Link Layer
How Peer Layers
Communicate
Hubs
IBM Cabling
IEEE 802.11
IEEE 802.12
IEEE 802.2
IEEE 802.3
IEEE 802.3 and IEEE
802.5 Media
IEEE 802.4
IEEE 802.5
IEEE 802.6
IEEE 802.9
Implementing a
Fault-Tolerant Design
Implementing Security
on Windows 95
Implementing Security
on Windows NT
Infrared Transmission
Initiating the
Troubleshooting Process
Installation
Installation
Installation
Installation
Installing Network
Adapter Cards
Intelligent Hubs
Internet Control
Message Protocol (ICMP)
Internet Protocol
(IP)
Internet Protocols
(TCP/IP)
ISDN and B-ISDN
Keeping Records
Laser Transmission
Leased Line Types
Link-State Routing
Local and Wide Area
Networks
Local Area Networks
(LANs)
Logging Events
Managing and Securing
a Microsoft Network
Managing User
Accounts and Groups Using Windows NT
Message Switching
Microwave
Mobile Computing
Models of Network
Computing
Modems
Monitoring Network
Traffic
Monitoring Network
Trends
Monitoring
Performance
Monitoring the
Network
Multiplexing
Narrow-Band Radio
Transmission
NDIS and ODI
NetBEUI
NetBIOS Background
NetBIOS Names
NetBIOS Names
NetWare IPX/SPX
Network Adapter Cards
Network Applications
Network File System
(NFS)
Network Layer
Addressing
Network Models:
Comparing Server-Based and Peer-to-Peer Configurations
Network Operating
Systems
Network Printing
Network Security
Network Topologies
and Architectures
Networking Concepts
and Components
Networking Essentials
Networking Standards
Networking Terms and
Concepts
Open Shortest Path
First (OSPF)
OSI Application Layer
Concepts
OSI Data Link Layer
Concepts
OSI Network Layer
Concepts
OSI Physical Layer
Concepts
OSI Presentation
Layer Concepts
OSI Session Layer
Concepts
OSI Transport Layer
Concepts
Packet Routing
Services
Packet Switching
Packets and Protocols
Passing Data on Token
Rings
Passive Hubs
Peer-to-Peer
Networking
Permissions
Physical and Logical
Topologies
Preparing Data
Printer Sharing with
Windows 95
Printer Sharing with
Windows NT
Protecting Data
Protocol Stacks
Protocols and
Protocol Layers
RAID 0
RAID 1
RAID 5
Reasons for Wireless
Networks
Recovering from
System Failure
Remote Terminal
Emulation (TELNET)
Repeaters
Repeaters
Resolving Hardware
Conflicts
Resource Sharing
Basics
Resources
Rights
Ring Topologies
Routers
Routers
Routing
Routing Algorithms
Routing Information
Protocol (RIP)
Rules and the
Communication Process
Satellite Microwave
Securing Hardware
Security for Printer
Resources
Sending Data
Serial Line Internet
Protocol (SLIP) and Point-to-Point Protocol (PPP)
Server-Based
Networking
Session Layer Session
Administration
Share-Level Security
on Windows 95
Sharing
Shielded Twisted-Pair
(STP) Cable
Simple Mail Transfer
Protocol (SMTP)
Spread-Spectrum Radio
Transmission
Standards
Standards
Organizations and the ISO
Star Topologies
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary of Cable
Characteristics
Synchronous
Transmission
Table 3.1
Table 3.2
Table 3.3
Table 4.1
Terrestrial Microwave
The Beaconing Process
The IEEE 802 Family
The OSI Reference
Model
The Public Telephone
Network
Thicknet
Thinnet
Time-Division
Multiplexing
Token Passing
Token Ring
Token Ring Cabling
Transmission Control
Protocol (TCP)
Transmission
Frequencies
Transmission Media
Transport Layer
Connection Services
Transport Protocols
Troubleshooting
Troubleshooting
Cables and Connectors
Troubleshooting Hubs
and MSAUs
Troubleshooting
Modems
Troubleshooting
Network Adapter Cards
Troubleshooting
Network Performance
Twisted-Pair Cable
Types of Coaxial
Cable
Uninterruptible Power
Supply
Unshielded
Twisted-Pair (UTP) Cable
User Accounts
User Datagram
Protocol (UDP)
User-Level Security
on Windows 95
Users
Using RAID
Using Troubleshooting
Tools
Virtual Circuit
Packet Switching
Virtual Circuits
Virus Protection
Wide Area Networks
(WANs)
Windows NT Networking
Wireless
Communications with LANs
Wireless Media
X.25
links