Shulou(Shulou.com)06/01 Report--

Collision domain:

Conflict range of electrical signals

Repeaters, hubs: collision domains cannot be divided

Because, the working object of the above equipment is electrical signals.

Bridges, switches: can split collision domains

Because the working object of the above equipment is not an electrical signal.

Is a "frame" with a certain format

The name of the data on each layer:

OSI model signals represent common equipment

Physical layer 0min 1 bit stream (electrical signal) network cable, repeater, hub

Data link layer frame bridges, switches

Network layer packet router

Transport layer

Application layer data flow

Basic configuration of network devices:

Switch >

Explanation:

Switch, which represents the name of the device

Cisco switches are all under that name by default

>, which represents the schema prompt

Used to tell the configuration staff what mode they currently belong to

System mode:

-user mode

Few commands and limited permissions

The first mode you enter when logging in to the device

-privileged mode

Rich commands and full permissions

Equivalent to the administrator of PC

# configuration mode

In this mode, the original information of the device can be changed.

Configuration commands are as follows: (help system -? And tab)

Switch > / / the mode when the user first logged in

Switch > enable / / user enters privileged mode

Switch# / / user is already in privileged mode

Switch#config terminal / / users are about to enter "configuration mode"

Switch (config) # / / user has entered "configuration mode"

Switch (config) # hostname Cisco-1 / / change the device name

Cisco-1 (config) #

Cisco-1 (config) # exit / / exit to the previous mode

Cisco-1#

Cisco-1#disable / / exits from privileged mode to user mode

Cisco-1 >

Cisco (config) # line console 0

Cisco (config-line) # end / / fallback directly to privileged mode

Cisco#

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Composition of network equipment: Cisco Linux Administrator

-Hardwar

Memory-RAM, random read memory

CPU

Flash-hard disk

ROM-read-only memory, read-only memory

Nvram-non-volatile memory

-softwar

System files-IOS (internet operating system)

Profile-

Running-config

Running configuration file

The file is saved in memory (RAM)

When the equipment is powered off, it is easy to lose.

Startup-config

Configuration files loaded at boot time

The file is saved in non-volatile memory (nvram)

Files will not be lost when the device is powered off

How to save the memory of running-config in startup-config?

Cisco# write

Essential meaning:

"copy" the contents of running-config to startup-config

The command to view the file:

Cisco# show running-config

Show startup-config

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How the devices on the network are managed:

-Local Management

Cable-console wire (reversal line)

Interface-console port (included with network equipment)

There is a default timeout when entering commands through this port

For 10 minutes

Cisco (config) # line console 0 / / enter the console port

Cisco (config-line) # exec-timeout 0 0

/ / turn off the timeout function

-remote management

That is, access to the management IP address of the device through the network

Management Interface-line vty (virtual access)

By default, remote access requires a password

And

Privileged password must be configured.

The configuration commands are as follows:

Cisco (config) # line vty 0 4

Cisco (config-line) # password shijiuda / / remote access password

Cisco (config-line) # exit

Cisco (config) # enable secret zhongguo / / privileged password

Note:

The number of vty supported varies with different types of devices

Remote connections follow line number when occupying vty lines

Size, from small to large to choose to use.

The authentication function under line vty is turned on by default. We can also close it.

But it is not recommended to do so, it is not safe!

Test commands:

PC > telnet 192.168.1.100

Verify the command:

Cisco# show running-config

Cisco# show user

Line culling:

Cisco# clear line x (only on real machines)

Configure the local login password:

Cisco (config) # line console 0

Cisco (config-line) # password nihao / / login password

Cisco (config-line) # login / / enable authentication

Note:

By default, console login does not require a password

Configure the privileged password:

Cisco (config) # enable password wohao

Cisco (config) # enable secret

/ / privileged password configured in this way

When the configuration file is encrypted

Delete privileged password:

Cisco (config) # no enable password

No enable secret

Delete the local login password:

Cisco (config) # line console 0

Cisco (config-line) # no password

To ensure that all passwords on the device are stored in encrypted form

Therefore, you can turn on the password encryption service on the device:

Cisco (config) # service password-encryption

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The equipment is restored to factory configuration:

Essentially, delete the startup configuration file of the device

1. Cisco#erase nvram (operation command of real device)

Cisco#erase startup-config (commands on the simulator)

2. Cisco#delete nvram:startup-config (real equipment)

View the storage location of the files on the device:

Csico# dir

Dir / all-file-system

Basic information collection of equipment:

Cisco# show version

1. Equipment model

2. IOS version

3. Memory

4 、 Flash

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Configure the switch with an IP address:

Cisco#show ip interface brief / / View interface brief information

Cisco#config terminal

Cisco (config) #

Cisco (config) # interface vlan1 / / enter the virtual port vlan1

Cisco (config-if) # no shutdown / / Open Port

Cisco (config-if) # ip address 192.168.1.100

255.255.255.0

Cisco (config-if) # end

Cisco#

Cisco# show ip interface brief / / verify the configured interface IP

Cisco# ping 192.168.1.1 / / Test the connectivity between the switch and PC

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