= '''VLSM Fundamentals''' =
== Introduction ==
=== Objective ===

:The primary goal of this page is to provide a simple explanation to the techniques for designing and planning LANs using VLSM. The materials presented here are presented for someone who may be at the first course level in the Networking Academy CCNA Exploration curriculum. Knowing how to subnet networks using VLSM quickly is a necessary skill needed as you prepare for your CCNA certifications.

=== Definitions ===

:VLSM - Variable-length subnet masking. This is a more practical way of subnetting a network by efficiently using the Host bits in the subnet.

:CIDR - Classless Inter-Domain Routing. This is based on VLSM subnetting of Class A, B and C networks.

== Typical Classful Networks ==

:This is the 'older' method of creating subnetworks. This is not an efficient use of IP addresses within a network. It is actually wasteful of IP addresses because all the subnets have the same number of hosts.

:Remember that when you subnet a classful network all of the networks will have the same number of hosts because they have the same subnet mask.

=== Basic CIDR understanding ===

::There are also a range of IP addresses you can only used privately, not on the internet.
:::These are the RFC 1918 private IP's:
:::Class A 10.0.0.0 to 10.255.255.255
:::Class B 172.16.0.0 to 172.32.255.255
:::Class C 192.168.0.0 to 192.168.255.255

::1 examine the number of bits borrowed for Host addresses.
::2 observe the most interesting octet. This will allow you to determine the subnet mask.
::3 determine the network increment (size of the network blocks) 256 - subnet mask = block size.

:the number of Networks is figured out by 2 to the Nth power - 2 ( N standing for the number of network bits borrowed).
::Remember that the number of networks cannot include all 0's or 1's. All 0's is the network address and the broadcast address is all 1's.

=== Steps to subnet in your head ===
::1
::2...
The following
:*Postfix
:*Send mail

== VLSM Design ==

::VLSM is the process where you are subnetting a subnet using varying subnet masks.
::Your IP plan will determine the basic layout of networks. Multiple solutions are possible.

::Requires forethought and planning. Current and future networks.

::IP Subnet Zero.

=== Steps for creating an IP plan using VLSM ===

::*
::*

== Implementing VLSM ==

:Make sure that your network assignments and subnet masks are accurate and that they fit your topology.

:Verify that your IP addresses and subnet masks to not crossover any binary and octal bit boundaries. If they are incorrect, you will receive an error when configuring router interfaces.

VLSM Fundamentals

2011-05-06T08:39:52Z

Jonk0002:

VLSM Fundamentals

2011-05-06T08:29:32Z

Jonk0002:

2011-05-06T06:01:38Z

Jonk0002:

VLSM Fundamentals

2011-05-06T05:42:30Z

Jonk0002:

= '''VLSM Fundamentals''' =
== '''Introduction''' ==
=== Definitions ===

:VLSM - Variable-length subnet masking. This is a more practical way of subnetting a network by efficiently using the Host bits in the subnet.
:CIDR -

=== Objective ===

:Provide a simple explanation

== Typical Classful Networks ==
:An 'older' method, wasteful use of IP addresses, not efficient use of IP address assignments within networks.
:Remember that when you subnet a classful network all of the networks will have the same number of hosts because they have the same subnet mask.

=== Basic CIDR understanding ===

::There are also a range of IP addresses you can only used privately, not on the internet.
:::These are the RFC 1918 private IP's:
:::Class A 10.0.0.0 to 10.255.255.255
:::Class B 172.16.0.0 to 172.32.255.255
:::Class C 192.168.0.0 to 192.168.255.255

::1 examine the number of bits borrowed for Host addresses.
::2 observe the most interesting octet. This will allow you to determine the subnet mask.
::3 determine the network increment (size of the network blocks) 256 - subnet mask = block size.

:the number of Networks is figured out by 2 to the Nth power - 2 ( N standing for the number of network bits borrowed).
::Remember that the number of networks cannot include all 0's or 1's. All 0's is the network address and the broadcast address is all 1's.

=== Steps to subnet in your head ===
::1
::2...
The following
:*Postfix
:*Send mail

== VLSM Design ==

::VLSM is the process where you are subnetting a subnet using varying subnet masks.
::Your IP plan will determine the basic layout of networks. Multiple solutions are possible.

::Requires forethought and planning. Current and future networks.

::IP Subnet Zero.

=== Steps for creating an IP plan using VLSM ===
::*
::*

== Implementing VLSM ==

:Make sure that your network assignments and subnet masks are accurate and that they fit your topology.

:Verify that your IP addresses and subnet masks to not crossover any binary and octal bit boundaries. If they are incorrect, you will receive an error when configuring router interfaces.

VLSM Fundamentals

2011-05-06T05:39:21Z

Jonk0002: Created page with "= '''VLSM Fundamentals''' = == Introduction == === Definitions === :VLSM - Variable-length subnet masking. This is a more practical way of subnetting a network by efficiently ..."

= '''VLSM Fundamentals''' =
== Introduction ==
=== Definitions ===

:VLSM - Variable-length subnet masking. This is a more practical way of subnetting a network by efficiently using the Host bits in the subnet.
:CIDR -

=== Objective ===

:Provide a simple explanation

== Typical Classful Networks ==
:An 'older' method, wasteful use of IP addresses, not efficient use of IP address assignments within networks.
:Remember that when you subnet a classful network all of the networks will have the same number of hosts because they have the same subnet mask.

=== Basic CIDR understanding ===

::There are also a range of IP addresses you can only used privately, not on the internet.
:::These are the RFC 1918 private IP's:
:::Class A 10.0.0.0 to 10.255.255.255
:::Class B 172.16.0.0 to 172.32.255.255
:::Class C 192.168.0.0 to 192.168.255.255

::1 examine the number of bits borrowed for Host addresses.
::2 observe the most interesting octet. This will allow you to determine the subnet mask.
::3 determine the network increment (size of the network blocks) 256 - subnet mask = block size.

:the number of Networks is figured out by 2 to the Nth power - 2 ( N standing for the number of network bits borrowed).
::Remember that the number of networks cannot include all 0's or 1's. All 0's is the network address and the broadcast address is all 1's.

=== Steps to subnet in your head ===
::1
::2...
The following
:*Postfix
:*Send mail

== VLSM Design ==

::VLSM is the process where you are subnetting a subnet using varying subnet masks.
::Your IP plan will determine the basic layout of networks. Multiple solutions are possible.

::Requires forethought and planning. Current and future networks.

::IP Subnet Zero.

=== Steps for creating an IP plan using VLSM ===
::*
::*

== Implementing VLSM ==

:Make sure that your network assignments and subnet masks are accurate and that they fit your topology.

:Verify that your IP addresses and subnet masks to not crossover any binary and octal bit boundaries. If they are incorrect, you will receive an error when configuring router interfaces.

CNT-2311-Chapter 9 Notes

2011-04-08T00:19:25Z

Jonk0002: Created page with "= '''Chapter 9''' = == Managing the Shell Environment == === Environment Variables === :Environment variables provide the means to pass named data (variables) to programs launch..."

= '''Chapter 9''' =
== Managing the Shell Environment ==
=== Environment Variables ===
:Environment variables provide the means to pass named data (variables) to programs launched from a shell.
:Environment variables usually have a preceding ($) when you are using it in a script and on a shell command line.
:Shells themselves also rely on environment variables.
:Environment variables may be manually assigned a value using the equal sign assignment operator.
:The variable becomes available to the programs you launch in your shell when you use the export command.
::Example: $ HOSTNAME=inverhills.lab07.com
:: $ export HOSTNAME
::Note that the two commands can simplfied into one statement
:: $ export HOSTNAME=inverhills.lab07.com
:A program that needs to know the TCP/IP hostname of the computer can refer to the $HOSTNAME to get this information.
:On a bash command line, use env to display all environment variables or you may refer to an single environment variable by using the echo command.

=== Common Environment Variables ===
:Any system may have several environment variable values set each relating to specific programs.
:Using command env alone, will display all environment variables that are currently set, otherwise it is used to run a program with a changed set of environment variables.
::Example: $ env | grep HOSTNAME
:: HOSTNAME=inverhills.lab07.com

:Use the echo command if you want to know the value of a single variable. If you pass a variable preceded by a ($) the value of the variable is returned.
::Example: $ echo $HOSTNAME
:: HOSTNAME=inverhills.lab07.com

:The following list has a few Common Environment Variables and their meanings
::SHELL: Holds the path to the current command shell
::PWD: Present working directory and maintained by the system
::HOME: Points to your home directory
::HOSTNAME: The current TCP/IP hostname of the computer
::PATH: Sets the path for a session and is unusually important. The PATH variable is typically built up in several configuration files, such as /etc/profile and in the .bashrc file in the user’s home directory
::MAIL: Holds the location of the user’s mail spool which is usually /var/spool/mail/username.
::PS1: This is the bash default prompt. PS1 includes variables of it’s own such as \u (for username) , \h (for hostname) and \W for working directory.
::LD_LIBRARY_PATH: Some programs use this to identify the directory where the library files may be located. This is similar to PATH.

=== Aliases ===
:Most Linux shells, including bash, support using command aliases. They are new names that you can give to regular commands.

:You can define aliases individually at any bash prompt, but typically they are included in your bash startup script.

:To implement an alias, use the following syntax: alias alias_name=‘commands’

=== Shell configuration ===
These files may be classified in a couple of ways:
Global files: These affect all users of a shell or are local files that affect one user
User/Login files: These are launched only by a login process or by non-login files that are launched by other processes

Global file types: Login file location - /etc/profile and in /etc/profile.d Non-Login file location - /etc/bashrc or /etc/bash.bashrc

User file types: Login file location - ~/.bash_login, ~/.profile, or ~/.bash_profile Non-Login file locations - ~/.bashrc

Global configuration files affect all users of a system; however, their settings may be overridden by individual users, either in user configuration files or in commands that the user may have entered themselves.

Skeleton files are files copied to the user’s home directory when the account was created. They are a set of files that include local bash startup files and are located in the /etc/skel directory. Changes made to these files only affect new accounts.

== Writing Scripts ==
As you use Linux you will more than likely encounter tasks that involve repetitive entry of commands at a shell prompt. Shell Scripts are simple programs written in a interpreted language that are embedded in the Linux shell which you use to type commands.
Most Linux systems use the bash shell by default, so more than likely shell scripts are written in the bash shell scripting language.

=== Beginning a Shell Script ===
The first line of the shell script identifies the shell being used to run it.
The first two characters are a special code which tell the Linux kernal that this is a script and that the rest of the line is the pathway to the program which will interpret the script. This line is refered to as the shebang, hashbang, hashpling or pound bang.
::Example: #! /bin/sh * /bin/sh as a symbolic link to /bin/bash

The hash mark ( # ) is a comment character. The script utility ignores this line, but the Linux kernal does not.
After writing the script, you make it executable by using the chmod command.
::Example: $ chmod a+x my-script

Here the +x option, adds execute permissions to a script called my-script and the a option supplies those permissions to all users.

=== Using Commands ===
Shell scripts can run commands both internally and externally to the script.
Using ampersand ( & ) at the end of each line in the script running a program file tells the shell to continue on to the next line without waiting for the previous line to finish.

Normal file manipulation commands are used in scripts.
::Examples of commands used are: ls, mv, cp, rm as well as grep, find, cut, sed, echo and mail.

=== Using Variables ===
Variables, or they can be called Parameters, may be passed to the script. The syntax used to identify a parameter is by using a leading dollar sign ( $ ) with a 0 - 9 number following. Example: $5

Another type of variable used in scripts receive their value from the output of a command. These variables have a leading dollar sign ( $ ) and are typically followed by a name beginning with a alphabetic character, A - Z. Example: $Addr

When assigning a variable the output of a command, that command needs to be enclosed with the back quote character ( ` ).

=== Using Conditional Expressions ===
Conditional expressions are used by the compound command and the test commands. Expressions may be unary or binary.
Unary expressions are often used to examine the status of a file.
The following list is a small sample of conditional commands and their test condition:
:-a file ,True if file exists
:-d file ,True if file exists and is a directory
:-f file ,True if file exists and is a regular file
:-s file ,True if file exists and has a size greater than zero

Conditional expressions use string operators and numeric comparison operators as well.
::Example: string1 == string2 The condition is True if the the two strings have equal values

Conditionals may combined together using a logical AND ( && ) or a logical OR ( | | ).

When conditionals are joined with &&, both sides of the expression must be True for the entire expression to the True.

When | | is used, if either side of the expression is True, the entire expression will be True.

=== Using Loops ===
These constructs tell a script to perform a certain task repeatedly until a stated condition is met ( or when it is no longer met).

The until command executes consequent-commands as long as test-commands has an exit status which is not zero.

:until command syntax is: until test-commands;
: do consequent-commands;
: done

The while command executes consequent-commands as long as test-commands has an exit status of zero.

:while command syntax is: while test-commands;
: do consequent-commands;
: done

=== Using Functions ===
These are used to group commands for later execution by referencing the single name for the group.

These are executed just like a "regular" command. When the name of a shell function is used as a simple command name, the list of commands associated with that function name is executed.

:Functions syntax: name () { command-list; } -The shell function is name. The body of the function is the command-list in between { and }.

== Managing E-mail ==
E-mail is one of the most important network services. Most Linux distributions have e-mail server software installed and configured with basic settings.

=== Understanding E-mail ===
SMTP: Simple Mail Transfer Protocol is a push mail protocol. It is designed to send data so SMTP is used thoughout most of the mail delivery system. The sending machine is the initiator of the mail transfer. SMTP servers are known as mail transfer agents (MTAs). SMTP will enable a message to be relayed through a set of SMTP servers.

POP and IMAP: These are both pull mail protocols. Post Office Protocol (POP) and Internet Message Access Protocol (IMAP) servers transfer the mail message to the receiving computer when a relay request is initiated.

A header is added by each server in the relay chain. This provides documentation to the path which the message has taken. It may be that a large number of servers are involved in the chain, but usually a message passes through 6 or less systems.

In general, a user’s mail server incoming messages are stored in a file in /var/spool/mail/username. This file or directory is known as the user’s mail spool.

=== E-mail Software ===
Linux supports several different e-mail servers. Generally, one of the major mail servers will be included in your system. If not, you will have to determine which to use and install it on your machine.

The following are four of the most popular e-mail servers use on Linux.
:*Postfix
:*Sendmail
:*Exim
:*qmail

=== Managing E-mail ===
The mailq program is the main tool available for e-mail management. Basically, the command shows the contents of the e-mail queue on all systems. This can be useful to you when the messages in a mail queue need to be cleared out.

== Managing Data with SQL ==
Structured Query Language (SQL) is a language used to retrieve data from a database or to store data on a database.

SQL is a language used to access data on a database. In principle, you may use any SQL package in Linux that meets your needs. Certain products may work best with a specific SQL package or even may require a particular one. You should research each package in detail before deciding on one. Some packages operate on the client-server model. One program (the server) manages the database, while another (the client) supplies users and programs access to the database.

=== SQL packages ===
MySQL can be pronounced My-S-Q-L , or commonly as My Sequel, and is a relation database management system.
Most major Linux distributions include MySQL in their packages. For a complete installation, you probably will
install multiple packages, such as a client, a server and probably development tools.
You can learn more at http://www.oracle.com/us/products/mysql/.

PostgreSQL is a powerful, open source object-relational database system and runs on all major operating systems.
Like MySQL, implementation most likely will have a client and server installed, along with additional support
packages. Information about PostgreSQL can be found at http://www.postgresql.org/.

SQLite is not a standalone database. It provides programs with a method to store data using a SQL interface within
the program. SQLite is a software library that implements a SQL database engine. This package is based
at http://www.sqlite.org/.

=== SQL basics ===
Pros and Cons: Pros are that SQL is a flexible language, it is universal and there are relatively few commands to learn.
Cons are that you need to have a detailed knowledge of the database and it's structure and that extracted
data may provide you with misleading results.

Row (also known as a tuple), represents a single object.

Column (also known as an attribute or field) represents a specific feature.

Commands are terminated by a semicolon ( ; ). It is good practice to use it, but not all commands require it.

Combination of rows and columns is referred to as a table. Databases may contain multiple tables and SQL may also support multiple databases.

=== Using SQL ===
Primary Keys have 1 or More Columns Used to Uniquely Identify a record.
All Columns Defined as PK’s MUST be populated

Foreign Keys are a Value on a table that references a Primary Key from a different table.

Joining tables are usually based on Primary / Foreign Keys.

SQL Command examples

''SELECT'': This statement returns a set of records from a table or view. It can be used in combination with JOIN to return a set of records from multiple tables. The set of records returned can be reduced by using the WHERE clause conditions. The order that they are returned can be set by using the ORDER BY clause.

:Most common form: SELECT field1, field2, etc FROM tableName
:: WHERE conditions ORDER BY listOfFields

''INSERT'': Adds new records (rows) to the table.
:Most common form: INSERT INTO tableName(field1,field2)
:: VALUES(value1,value2)

''UPDATE'': Is most often used in combination with the WHERE clause to update a record in a table.
:Most common form: UPDATE tableName SET field1=value1, field2=value2
:: WHERE condition

''DELETE'': When you need to delete a row in your table, or a set of rows, you will use this statement.
:Most common form: DELETE FROM tableName WHERE condition

WHERE: This clause specifies what set of records the operation should be performed on.
:The most common are: =, <>, <, >, IN, and LIKE operands.

Franske CNT-2311

2011-04-07T19:06:35Z

Jonk0002: /* Chapter Project Notes */

This is the homepage for the CNT-2311 classes taught by Dr. Ben Franske.

== General Course Information ==
* [http://spreadsheets.google.com/a/ihcnt.net/viewform?formkey=dDlkdms5VDhkSktkTHRVaVNoVDh0UlE6MQ First Day Sign In Form]
* [[Franske CNT-2311 Syllabus|Course Syllabus]]
* [[Franske CNT-2311 SP11 Schedule|Spring 2011 Course Schedule]]
* [[Franske CNT-2311 Chapter Project SP11 Groups|Spring 2011 Chapter Project Groups]]
* [[Franske CNT-2311 Labs|Lab List]]
* [[Franske CNT-2311 Chapter Project Assignment|Chapter Project Assignment]]
* [[Franske Lab Report Format|Lab Report Format]]

== Chapter Project Notes ==
[[CNT-2311-Chapter 2 Notes]] 
[[CNT-2311-Chapter 3 Notes]] 
[[CNT-2311-Chapter 4 Notes]] 
[[CNT-2311-Chapter 5 Notes]] 
[[CNT-2311-Chapter 7 Notes]] 
[[CNT-2311-Chapter 8 Notes]] 
[[CNT-2311-Chapter 9 Notes]] 
[[CNT-2311-Chapter 10 Notes]] 

== Projects ==

* [[Dual Booting Ubuntu and Windows 7]]
* [[GUID Partiton Table]]
* [[Linux VLAN Trunking]]
* [[Installing Webmin]]
* [[Nat Masquerading and Firewall]]
* [[Control Web Access With Squid]]
* [[Installing MyBB Forum]]
* [[openvpn]]
* [[Zoneminder]]
* [[Understanding Linux Permission Sets]]
* [[Franske CNT-2311 SP10 Commands|Spring 2010 Commands by Session]]
* [[Converting VMWare .vmdk To VirtualBox .vdi Using Qemu+ and VBoxManage]]
* [[Linux command guide]]
* [[Windows File Sharing and Printer Sharing with SAMBA]]
* [[How to Setup NAT]]
* [[Linux-command-list]]

== Resources ==
* [[Writing Moodle Questions]]
* [[Editing Moodle Questions]]
=== Software ===
* [http://www.virtualbox.org Virtualbox]
** [[VirtualBox Startup Script]]
===Regular Expressions, Grep and SED===
* [http://www.zytrax.com/tech/web/regex.htm Regular Expressions - A Simple User Guide]
* [http://linuxreviews.org/beginner/tao_of_regular_expressions Tao of Regular Expressions]
=== Major Linux Distributions ===
* [http://www.debian.org Debian]
** [http://www.ubuntu.com Ubuntu]
* [http://www.redhat.com Redhat Enterprise Linux (RHEL)]
** [http://centos.org CentOS]
** [http://fedoraproject.org Fedora]
* [http://www.gentoo.org Gentoo]
* [http://www.opensuse.org OpenSUSE (Novell)]
=== Online Linux Tutuorials ===
* [http://www.linux.org/lessons/beginner Beginning Linux from Linux.org]
* [https://help.ubuntu.com/community/PostfixBasicSetupHowto Postfix Basic Setup]
* [http://lartc.org Linux Advanced Routing & Traffic Control (Advanced Networking)]