Introduction to router is a layer 3 device or it is network layer device which is used for to connect different network
Introduction to router
What is router?
Router is a layer 3 device or it is network layer device which is used for to
connect different network with each other and judge the shorest path to
transfer the data.
Manufacture of router:-
- Cisco
- Juniper
- 3com
- Hp
- D-lint...etc.
Internal component of router:-
- Microprocessor:-
in this microprocessor we use the RISC technology it is available 70MHz up
to 1.0 GHz and above. Generally Motorola companies microprocessor is
use.
- Ram:-
it is use to save running configuration available in 16, 32, 64, 128,256
MB.
- Flash:-
this is hdd of router which is used to store os configuration of the
router. Available in 16, 32, 64, 128 MB.
- Nvram:-
it consist the startup configuration.
- Rom:-
it is bios of router.
External component of router
- Console:-
this is use for to access router from PC.
- Serial port:-
use for to connect one router with another router in WAN or local place it
is available in 60 pin 32 pin.
- Ethernet:-
this is use to connect the router with switch. It is available in,| Ethernet | 10 Mbps |
| Fast ethernet | 100 Mbps |
| Giga byte ethernet | 10 Gbps |
- Auxiliary port:-
this is use to connect dial-up model.Layer of router
Router is divided logically by cisco in following 3 layer.
- Access layer:-
this is the company layer router or desktop router in this there are
800, 900, 1400, 1700, 1800, 2500 series.
- Distribution layer:-
this is used for ISP to distribute the network. It is included 2600,
2800, 3500, 3600, 3700, 3900, 4500, 5600 series.
- Core layer:-
this is backbone, mostly use for global ISP. It is included 2600, 2800,
3500, 3700, 3900, 4500, 5600 series.How to access router in PC
For win XP and 2003 server
Start --- program --- accessories --- communication --- hyper terminal ---
type name --- ok --- select com l --- ok --- restore default --- ok.
Modes of router
Router>:-user mode some command are work.
Router# :- this is the privilege mode all show commands, verification,
save, copy, erase of router done from this mode.
Router (config)# :- this is configuration mode all the configuration of
router done.
Editing tool
Ctrl A - move cursor to beginning of the line
Ctrl E - move cursor to end of the line
Esc B - move cursor back one word
Esc F - move cursor forward by one word
Ctrl D - or backspace - deletes a single character
Ctrl U - erse a line
Ctrl R - redisplays a line
Ctrl W - erase a word
Ctrl Z - ends the configuration mode and returns to exec mode
Tab - finishing typing a command
Ctrl P - shows last command typed
Ctrl N - shows previous command entered
Booting process of router
POST (Power On Self-Test):-
1. When any device start at that time BIOS check the configuration of that
device.
2. When you start router at that time POST is used to test router hardware.
3. After that the POST load, the boot strap program locates the cisco IOS
and load it into ram.
4. Locating and loading IOS into RAM the location of IOS file is specified
by value of configure registry setting.
5. The bits in the setting can instruct the device to load IOS file from
following location from flash memory and registry setting is 0x2102.
6. After IOS is loaded boot start up program search for startup configure
file in NVRAM.
7. This file contains interface address, routing information, passwords and
other configured parameter.
8. If there is no configuration file the router prompts the user to enter
into setup mode to begin configuration process.
9. If a startup configuration file is found then hostname will display the
router has successfully loaded IOS and configure file.
Basic configuration of router
IOS Basic Commands:-
| Router >? | Help |
| Router >show? | Lists all the commands in Show |
| Router >s? | Lists all the commands starting with ‘S’ |
| Router > | show terminal shows terminal configuration and history buffer size |
| Router > | show version shows the version |
| Router > | show flash shows details of ‘flash’ |
| Router > | enable to enter privilege exec mode |
| Router # | show history show last ten commands |
| Router # | terminal history size 20 to set history size to 20 |
| Router # | showrunning-configuration to display contents of Dynamic RAM |
How to move Forward:-
Router>en
Router #config t
Router(config)#
How to move back:-
Router (config)#Ctrl+z OR exit OR end
Router #
Exit – Go back to the or exit the current mode
End or Ctrl+z – Go to the privilege mode
How to provide host name
Router>en
Router#config t
Router (config)#hostname R1
R1(config)#exit
R1#copy running-config startup-config OR
R1#wr
Banner:-
Banner is used to display some message when user login to the router it is
display before user mode. How to provide Banner
Router>en
Router#config t
Router(config)#banner motd #
Enter the text message end with the #character This is universal
router#
Router (config)#exit
Router #wr
How to remove banner
Router>en
Router#config t
Router (config)# no banner motd #
Router (config)#exit
Router #wr
How to provide IP address on interfaces
Fast Ethernet:-
Router>en
Router#config t
Router (config)#int f0/0
Router (config-if)#ip add 10.0.0.1 255.0.0.0
Router (config-if)#no shut
Router (config)#ctrl+z
Router #wr
Serial port:-
It is use to connect one router to another router in local LAN or WAN it is
use DTE and DCE
Provide IP Address on Serial port:-
Router>en
Router#config t
Router (config)#int s1/0
Router (config-if)#ip add 20.0.0.1 255.0.0.0
Router (config-if)#no shut
Router (config)#ctrl+z
Router #wr
Show commands
Show commands are useful for to view the configuration information all
related information above router, view the routing table. This command only
works in privilege mode but, if you use “do” before the show command then it
is work in configuration mode also.
Router # sh version
This command will be used to view information aboutIOS version, router
model, IOS file, memory information, interface information, registry
information.
Router# sh flash
This is use for to view the information about flash IOS file use available
memory.
Router# sh interface
This is use for to view information about all interface connected into
router serial port,fast Ethernet port.
Router# sh interface brief
This command is very helpful to view all the very brief information about
all connected interface briefly.
Router# shint f0/0
This command is use to view particular interface information of fast
Ethernet port
Router# sh controller s1/0
This command use to view the information about serial port like cable
connected to DTE (Data Terminal Equipment) or DCE (Data Communication
Equipment) Cable.
Router# sh clock time
Use to view current date
How to set date and time:-
Router# clock set 5:10:30 2 mon 22 2016
Router# sh ip protocol
This command is use for to view the all routing protocol information.
Router# sh history
This is use for previous use commands history it display max 10 commands
history by default you will able to change history.
By default history size is 10 then if you want to change history size
then you required to use following commands.
Router# sh terminal
Router # terminal history size 50
You can put any value instead of 50 in above command
Router# sh running config
This command is useful for to view the configuration is work in RAM.
Router# sh startup-configuration
Display the configuration in the startup.
Router# sh users
Display the user which is connected to the router.
Router # sh dhcp server
Display the DHCP server information.
Password of Router
We are able to provide password to the router for protection. We provide
Line Console, Line VTY (VirtualTeletYpe)password, enable secret password,
enable password.
Line Console password:-
This password will be ask whenyou login to router from console line it will
be ask before user mode.
Router>en
Router#configure t
Router (configure)#line console 0
Router (configure-line)#pass ccna
Router (configure-line)#ctrl+z
Router #wr
How to remove line console password
Router>en
Router#config t
Router (config)#line console 0
Router (config-line)# no pass
Router (config-line)#ctrl+z
Router #wr
Line vty password (virtual terminal password):-
Router>en
Router#config t
Router (config)#line vty 0 4
Router (config-line)# pass ccna
Router (config-line)#login
Router (config-line)#ctrl+z
Router #wr
How to remove line vty password
Router>en
Router#config t
Router (config)#line vty 0 4
Router (config-line)#no pass
Router (config-line)#login
Router (config-line)#ctrl+z
Router #wr
Enable secret password:-
This is use for to provide secretly when user move from user mode to
privilege mode.
Router>en
Router # config t
Router (config)#enable secret ccna
Router (config)#ctrl+z
Router #wr
How to remove enable secret password
Router>en
Router#config t
Router (config)#no enable secret
Router (config)#ctrl+z
Router #wr
Enable password:-
This is also secure to user mode to privilege mode but if we use enable
secret the password will not ask because it is not interrupted.
Router>en
Router#config t
Router (config)#enable pass ccna
Router (config)#ctrl+z
Router #wr
How to remove enable password
Router>en
Router#config t
Router (config)# no enable pass
Router (config)#ctrl+z
Router #wr
Service password encryption:-
When you fill the password some password not encrypted it is display in
running configuration to encrypt it you must use the service password
encryption command.
Router>en
Router#config t
Router (config)# service pass-encryption
How to break Router password
When you fill the password at that time the registry value is 0x2102, if
this value is set then each time when you start router it will ask password.
But if you set registry value 0x2142 then startup configuration will not ask
ignore
the password.
Step 1: Press on/ off button of router
Step 2: Press ctrl+pause break button
ROMmon (Read Only Memory monitor) mode will appear then,
Step 3: Rommon1> confreg 0x2142
Step 4: Rommon 2>i or reset
Router will be reset and Message appear “would you like to enter
initial
configuration y/n…….n”
Router>en
Router#config t
Router (config)#line vty 0 4
Router (config-line)# pass ccna
Router (config-line)#login
Router (config-line)#ctrl+z
Router #wr
Router>en
Router#config t
Router (config)#enable secret ccna
Router (config)#configure-register 0x2102
Router (config)#ctrl+z
Router #wr
Router# reload
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