Getting started with Cisco Routers 1

First look at the memory of one of the routers ' internal components

RAM: Random access memory, equivalent to the memory of the computer, with volatile (all stored content is lost after a power outage), running Master

the software is an iOS image and a configuration file.

ROM: Read-only memory, which resides in some of the micro-code that is used to start and maintain the basic functions of the router, which is non-volatile.

Flash: Flash, equivalent to the computer's hard disk, mainly used to store the iOS software image, to maintain the normal operation of the router, with non-volatile

Of

NVRAM: Non-volatile random access memory, primarily storing boot configuration files (startup-config), with an important content

is the Configurationregister (configuration register) used to control the boot of the router

First, basic configuration preparation work

1. Whether it is a router or a switch, iOS will return to the initial interface for a period of time without configuring the console.

Example: Router Con0 is now available

Press RETURN to get started.

To avoid this, you can modify the session time-out time, command "Exet-timeout 0 0", where the first "0" represents a split

Clock, the second "0" stands for seconds. Set to "0 0" means never timeout, command as follows, enter global mode first

Router (config) #line con 0

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

2. Sometimes the console will automatically display some information, which will interrupt the input command,

Example: *mar 1 00:03:35.707:%sys-5-config_i:configured from the console by console

To avoid such situations, you can enable display synchronization by using the following command, in global mode

Router (config) #line con 0

Router (config-line) #Logging Synchronous Configuration command can also be abbreviated as Logg syn

3. If you enter the wrong command in privileged mode, the router will mistakenly assume it is a domain name, and the device will use the broadcast method to perform DNS

query until DNS fails, this process can be delayed for a long time.

Example: *mar 1 00:06:12.951:%sys-5-config_i:configured from the console by console

Router#shrun

Translating "Shrun"

Translating "Shrun"

% Unknown command or computer name, or unable to find computer address

To avoid this situation, you can disable DNS lookups and go to the global schema

Router (config) #no ip domain-lookup disable command

Second, configure the IP address ( For example, F0/1 interface configuration IP is 192.168.1.1, subnet mask is 255.255.255.0)

Router (config) #int f0/1 into F0/1 interface

Router (config-if) #ip address 192.168.1.1 255.255.255.0 configuring IP and Subnet Masks

Router (config-if) #no shoudown Activation Interface

Third, configure the privileged password to the same as the switch

Route (config) #enable password 123 Configure plaintext password to 123

Route (config) #enable secret 456 config cipher for 456

Similarly, when both passwords are configured at the same time, the ciphertext password takes effect

Four, router password recovery

Step one, restart the router and press the Ctrl+breack key at the same time to interrupt iOS loading, the router enters ROM monitor mode

Step two, change the value of the configuration register to 0x2142, indicating that the configuration of the Startup-config is ignored at startup, and then restart

Rommom>confreg 0x2142 Modifying the value of a register

rommon>reset restarting the router

Step three, after restarting the router will not be able to load the configuration file because it modifies the value of the configuration register, so the password does not appear.

After entering configuration mode, manually load the configuration file in

router>en en entering privileged mode

router#copy startup-config running-config before loading the configuration file

Step four, after loading the previous configuration file, use the show Run command to see what password was configured before, you can use the above mentioned

to the Set password changes individually

Step five, after the password is reset, go to the global mode to change the value of the configuration register back, and save it

Router (config) #config-register 0x2102 Modify the value of the configuration register in global mode

Router (config) #exit exit Global mode

Router#copy running-config startup-config Save Configuration

Getting started with Cisco Routers 1