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master:cnd:cisco-config [2016/03/24 09:47] (current)
philip created
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 +====== Cisco Config Introduction ======
 +
 +===== Cisco router components: Memory types =====
 +
 +  * RAM
 +    * Stores packet buffers, ARP cache, routing table, software code and data structures necessary for router operation. Running configuration and decompressed IOS code is stored in RAM
 +  * ROM
 +    * Contains basic software for hardware testing and initialization
 +  * Flash
 +    * Stores IOS and backup configuration files. Not volatile
 +  * NVRAM (non-volatile RAM)
 +    * Saves router configuration
 +
 +===== Cisco router components: Software =====
 +
 +  * POST
 +    * Power-on Self-Test. Stored in ROM. Checks basic router functions ​
 +  * Bootstrap
 +    * In ROM. Initiates router and loads IOS
 +  * ROM Monitor
 +    * In ROM. Used for tests and troubleshooting. Basic interface for troubleshooting low-level issues
 +  * IOS (Internetwork Operating System)
 +    * Provides all of the higher-level router functionalities
 +
 +
 +
 +===== Configuration Register =====
 +
 +  * Controls various low-level settings
 +    * Tells router to load or ignore NVRAM configuration at startup
 +    * Terminal behaviour (e.g. serial speed)
 +  * Current value can be seen with
 +    * show version
 +  * Most common settings are:
 +    * 0x2102 - normal
 +    * 0x2142 - ignore configuration
 +
 +===== Where is the configuration?​ =====
 +
 +  * Router always has two configurations
 +    * running-config
 +        * In RAM. Shows which parameters are currently in use.
 +        * `show running-config`
 +        * Modified with `configure terminal` command
 +    * startup-config
 +        * In NVRAM. Loaded by router in next reboot
 +        * This is where the running-config is saved
 +        * `show startup-config`
 +
 +===== Configuration backups =====
 +
 +  * You can store configuration in other places
 +    * In router’s Flash memory
 +    * In a server, via TFTP
 +  * Can be copied around with copy command
 +    * `copy running-config startup-config`
 +        * or `write memory` (old style)
 +    * `copy running-config tftp`
 +    * `copy startup-config tftp`
 +    * `copy startup-config flash:​saved-config`
 +    * `copy flash:​saved-config startup-config`
 +
 +===== When the router has no configuration.... =====
 +
 +  * It asks `Would you like to enter the initial configuration dialog? [yes/no]:`
 +  * Just say *n* (no)
 +    * otherwise you get a tedious series of questions to answer
 +
 +===== Access modes =====
 +
 +  * User EXEC
 +    * Limited access. Show interface state, etc.
 +    * `Router>​`
 +  * Privileged EXEC (enabled mode)
 +    * Detailed examination,​ manipulate configuration and files, run tests, debugging, etc.
 +    * `Router#`
 +  * ROM Monitor
 +    * Password recovery and IOS installation
 +    * `rommon 1>`
 +
 +===== Management input sources =====
 +
 +  * Console
 +    *  Direct access via serial port
 +  * Auxiliary Port
 +    * Access via Modem
 +  * Virtual Terminals (VTY)
 +    * Telnet/SSH
 +
 +===== Changing the configuration =====
 +
 +Commands are activated immediately. So be careful when typing! ​
 +
 +When working on serial console or via Telnet or SSH, commands can be copied from a text file and pasted into the terminal
 +
 +  router>
 +  router>​enable
 +  ... type password ...
 +  router#
 +  router# configure terminal
 +  router(config)#​
 +  ... type commands ...
 +  router(config)#​ end
 +  router# write memory
 +
 +===== How to tell where you are =====
 +
 +  Router> - USER EXEC
 +  Router# -  PRVILEDGED EXEC
 +  Router(config) - Global configuration
 +  Router(config-if) - Interface configuration
 +  Router(config-subif) - Sub-interface configuration
 +  Router(config-route-map) - Route-map configuration
 +  Router(config-router) - Routing protocol configuration
 +  Router(config-line) - Line configuration
 +  rommon 1> - ROM Monitor
 +
 +===== Context Help =====
 +
 +Use "?"​ to obtain a list of commands available in your current configuration mode
 +
 +  Router(config)#?​
 +  Configure commands:
 +    aaa                         ​Authentication,​ Authorization and Accounting.
 +    aal2-profile ​               Configure AAL2 profile
 +    access-list ​                Add an access list entry
 +    alarm-interface ​            ​Configure a specific Alarm Interface Card
 +    alias                       ​Create command alias
 +    appfw                       ​Configure the Application Firewall policy
 +    application ​                ​Define application
 +    archive ​                    ​Archive the configuration
 +    arp                         Set a static ARP entry
 +    ...
 +
 +
 +
 +===== Online help =====
 +
 +
 +Use "?"​ also to see all possible parameters to an incomplete command:
 +
 +  Router(config)#​username ?
 +    WORD  User name
 +  Router#show ?
 +    aaa                       Show AAA value
 +    aal2                      Show commands for AAL2
 +    access-expression ​        List access expression
 +    access-lists ​             List access lists
 +    accounting ​               Accounting data for active sessions
 +    ...
 +
 +
 +===== Command completion =====
 +
 +Use the Tab key to complete a command
 +
 +  router(config)#​int<​TAB>​
 +  router(config)#​interface et<​TAB>​
 +  router(config)#​interface ethernet 0
 +  router(config-if)#​ip add<​TAB>​
 +  router(config-if)#​ip address n.n.n.n m.m.m.m
 +  ​
 +You can just type the abbreviated form if it's unambiguous
 +
 +  router(config)#​int e 0
 +  router(config-if)#​ip add n.n.n.n m.m.m.m
 +
 +===== Moving faster around the command line =====
 +
 +Move within command history:
 +  * [Cursor Up] - Previous command
 +  * [Cursor Down] - Next command
 +
 +Line editing:
 +  * [Cursor Left] and [Right] - move within the line
 +  * Ctrl-a : move to beginning of line
 +  * Ctrl-e : move to end of line
 +  * Ctrl-k : delete until end of line
 +
 +===== Verifying and troubleshooting =====
 +
 +  show running-config
 +  show run interface f0/0
 +  show ip int brief
 +  debug ip ospf hello / events / adj
 +  show log
 +  show version
  
master/cnd/cisco-config.txt · Last modified: 2016/03/24 09:47 by philip