Chapter 2 Flashcards
Operating Systems
*All networking equipment dependent on operating systems
-The operating system on home routers is usually called firmware
-Cisco IOS – Collection of network operating systems used on Cisco devices
Operating Systems
*Shell provides the user interface and allows interaction between user and kernel. This can be command line or graphical
*Kernel is the core of the operating system that interacts with the hardware.
Location of the Cisco IOS
Cisco IOS stored in Flash
-Non-volatile
-Can be overwritten
-IOS copied from flash to
RAM to run
-IOS with new features can
be installed if device has
enough Flash and RAM
Console Access Method
Console Port
-Device is accessible even if not configured
-Allows configuration
commands to be entered
-Should be configured
with passwords to
prevent unauthorized
access
-Device should be in a secure room so console port can’t be accessed
Telnet, SSH, and AUX Access Methods
Telnet
*Method for remotely
accessing the CLI over a
network
*Require one active
configured interface
*Clear text is sent
between end device and
intermediary device
Secure Shell (SSH)
*Remote login similar to
Telnet, but uses
encryption
Aux Port
*Uses telephone line
(dialup)
Terminal Emulation Programs
Software available for connecting to a networking device:
*PuTTY
*Tera Term
*HyperTerminal
Cisco (IOS) modes
In order from most basic to most specialized, the major modes are:
User executive (User EXEC) mode – the intermediary device always boots into this mode
Privileged executive (Privileged EXEC) mode
Global configuration mode
Other specific configuration modes, such as Interface configuration mode.
Each mode has a distinctive prompt
Global Configuration Mode and Submodes
The show version Command
This command displays information about the currently loaded IOS version, along with hardware and device information.
Software Version- IOS software version (stored in flash)
Bootstrap Version- Bootstrap version (stored in Boot ROM)
System up-time- Time since last reboot
System restart info- method of restart (e.g., power cycle, crash)
Software image name- IOS filename stored in flash
Router Type and Processor type- Model number and processor type
Memory type and allocation (Shared/Main)- Main Processor RAM and Shared Packet I/O buffering
Software Features- Supported protocols / feature sets
Hardware Interfaces- Interfaces available on the device
Configuration Register- Sets bootup specifications, console speed setting, and related parameters
The startup config and the running config
Cisco Commands - Check Configuration
Configuration changes made in the running configuration will affect the operation of the switch/router immediately!
If router is rebooted or reloaded, running config is lost!
Configuration Files
Startup config is saved using the copy running-config startup-config command
Startup configuration is removed by using theerase startup-config
Switch#erase startup-config
Setting Passwords
enable password– Limits access to the privileged EXEC mode
enable secret – Encrypted, limits access to the privileged EXEC mode
Encrypting Password Display
service password-encryption
Prevents passwords from showing up as plain text when viewing the configuration
Banner Messages
*Important part of the
legal process in the event
that someone is
prosecuted for breaking
into a device
*Wording implying a login
is “welcome” is not
appropriate
IP Addressing of Devices
*Each end device must be configured with an IP address.
*Structure of an IPv4 address is called dotted decimal.
*With an IPv4 address, a subnet mask is also necessary.
Example
IP Address: 192.168.1.1
Subnet Mask: 255.255.255.0
Network Address: 192.168.1.0
Broadcast Address: 192.168.1.255
Manual IP Addressing – IPv6
*IPv6 addresses are 128 bits
*Every four bits is represented by a single hexadecimal digit.
*Groups of four hexadecimal digits are separated by a colon “:”.
*IPv6 addresses are not case-sensitive
Automatic IP Addressing using a DHCP Server
Checking a PC’s IP Configurationusing ipconfig
*Go to command line
(cmd) and enter ipconfig
or ipconfig/all
Each device on the LAN should have a different IP address.
Test the Loopback Address on an End Device
Setting Passwords
Passwords can be set for the console port to add security
Passwords for Telnet access
*This allows us to remove
the rollover cable, and
access the switch/router
via the network cabling.
Remotely managing Switches/Routers
*The device must have an
IP address
*Router – assign an IP
address to an interface
*Switch – assign an IP
address to a Switch
Virtual interfaces (SVIs).
If remote access required
across a network (via a
router), switch must also
have a default gateway
address.
Configuring a SVI
This sets up up the virtual interface. Before remote access from another PC on the LAN, the switch needs Telnet configured and either a normal or secret password set.
Configuring a Switch Default Gateway
This allows remote PC’s from a different network to access the switch.
The following command in config mode sets the switch’s default gateway:
Switch(config)# ip default-gateway 192.168.10.254
What three things need to be configured in Cisco iOS to allow you to configure a switch on the same subnet?
1.Enable password
2.SVI /VLAN1 with IP
address and up
3.Telnet password and
login command
Context-Sensitive Help
Command Syntax Check
Hot Keys and Shortcuts
Tab – Completes the remainder of a partially typed command or keyword.
Ctrl-R – Redisplays a line.
Ctrl-Z – Exits the configuration mode and returns to user EXEC.
Down Arrow – Allows the user to scroll forward through former commands.
Up Arrow – Allows the user to scroll backward through former commands.
Ctrl-shift-6 – Allows the user to interrupt an IOS process such asping ortraceroute.
Ctrl-C – Exits the current configuration or aborts the current command.
