Cisco router Entry 1

Cisco router Entry 1
First, let's take a look at the Memory RAM of one of the vro's internal components: Random Access to the memory, which is equivalent to the memory of the computer and is volatile (all storage content will be lost after power failure ), the main software running is the IOS image and configuration file. ROM: read-only memory, which resident some microcodes used to start and maintain basic vro functions and is non-volatile. Flash: Flash Memory, equivalent to a computer's hard disk, is mainly used to store IOS software images, maintain the normal operation of the router, with non-loss resistance. NVRAM: non-volatile random access memory, mainly stores the startup configuration file (startup-config), and also has an important content: ConfigurationRegister (configuration register) used to control the start of a vro. 1. Basic configuration preparation, whether it is a vro or a vswitch, after a period of time without configuring the console, IOS will return to the initial interface. For example, Router con0 is now available Press RETURN to get started. to avoid this problem, you can modify the Session timeout time. The command "exet-timeout 0 0" indicates minutes, and the first "0" indicates seconds. If it is set to "0 0", the system never times out. The command is as follows: enter global mode Router (config) # line con 0 Router (config-line) # exec-timeout 0 02. sometimes the console automatically displays some information, which interrupts the input command, for example, * Mar 1 00:03:35. 707: % SYS-5-CONFIG_ I: Configured from console by console to avoid this kind of situation, you can enable display synchronization with the following command, in global mode Router (config) # line con 0 Router (config-line) # The logging synchronous configuration command can also be abbreviated as logg syn3. if the command is entered incorrectly in privileged mode, the Router will mistakenly think it is a domain name, at this time, the device will use the broadcast method to perform DNS queries until the DNS fails, this process may be delayed for a long time. For example, * Mar 1 00:06:12. 951: % SYS-5-CONFIG_ I: Configured from console by console Router # shrun Translating "shrun" Translating "shrun" % Unknown command or computer name, or unable to find computer address to avoid this type of situation, you can disable DNS lookup and enter the global mode Router (config) # no ip domain-lookup to disable command 2. Configure the ip address (for example, the ip address configured for the f0/1 interface is 192.168.1.1, the subnet mask is 255.255.255.0) Router (config) # int f0/1 to enter the f0/1 interface Router (config-if) # ip address 192.168.1.1 255. 255.255.0 configure IP address and subnet mask Router (config-if) # no shutdown activation Interface 3. Configure the privileged password to be consistent with the switch Route (config) # enable password 123 configure the plaintext password as 123 Route (config) # enable secret 456 configure the ciphertext password as 456. Similarly, when both passwords are configured at the same time, the ciphertext password takes effect. 4. Step 1. Restart the vro and press Ctrl + Breack to interrupt IOS loading. The vro enters ROM Monitor mode. Step 2, change the configuration register value to 0x2142, indicating that the startup-config configuration is ignored at startup, restart rommom> confreg 0x2142 to modify the value of the Register rommon> reset to restart the vro Step 3. After the restart, the vro cannot load the configuration file because the value of the configuration register is modified, therefore, no password is displayed. After entering the configuration mode, manually load the configuration file into the Router> en to enter the privileged mode Router # copy startup-config running-config Step 4 before loading the configuration file, after the previous configuration file is loaded, run the show run command to check which passwords have been configured. You can change the passwords one by one using the settings mentioned above Step 5. After the passwords are reset, in global mode, change the value of the configuration register and save it. Then, you can modify the value of the configuration register Router (config) # config-register 0x2102 in global mode) # exit global mode Router # copy running-config startup-config save Configuration