Cisco routers are manageable network devices. It means that they have the Cisco IOS software for network and internetwork management. The Cisco’s IOS software delivers network services and enabled networked applications. The Cisco IOS is the CLI based software at which you can execute Cisco IOS commands, and is the software used on the vast majority of Cisco Systems routers and current Cisco network switches.
Cisco Commands
There are more than 2,000 Cisco router commands in the latest version of Cisco router IOS software including the basic router commands along with the advanced level router commands such as Cisco wireless router commands. The Cisco router IOS have different executable modes with different prompts. You can use these modes for executing different tasks. Each mode has a set of specific commands.
Cisco IOS User Interface Fundamentals
Using a command line interface you have to keep in mind the following things
- Operations vary on different internetworking devices
- Type or paste entries in the console command modes
- Enter key instructs device to parse and execute the commands
- Two primary EXEC modes are user mode and privileged mode for executing basic Cisco commands
- Command modes have distinctive prompts
Cisco IOS Software Exec
There are two main EXEC modes for entering commands:
User Mode
- Limited examination of router
- Command prompt on the router is Router
Privileged (or enabled) Mode
- Detailed examination of router
- Enables configuration and debugging
- Prerequisites for other configuration modes
- Command prompt on the router is Router#
Configured versus Unconfigured Router
After completing the booting process, the configured Cisco router will prompt in user-mode prompt while the Cisco router will prompt in setup mode for initial configuration dialogue if there is no configuration in the memory.
Cisco Router Setup Mode
The Cisco router setup mode commands are as follows:
Setup: The Initial Configuration Dialog
Router # setup
System Configuration Dialog
Continue with configuration dialog? [Yes/no]: Y
At any point you may enter a question mark “?” for help
Use ctrl-c to abort the configuration dialog at any prompt
Default settings are in square brackets “[ ]”
Basic management setup configures only enough connectivity for management of the system, extended setup will ask you to configure each interface on the system
Would you like to enter basic management setup? [Yes/no] n
Setup Interface Summary
First, would you like to see the current interface summary? [Yes]
Setup Global Parameters
Configuring global parameters:
Enter host name [router]: R1
The enable secret is the password used to protect access to Privileged and configuration modes. This password, after entered, becomes encrypted in the configuration.
Enter enable secret: Cisco
The enable password is used when you do not specify an enable secret password, with some older software versions, and boot images.
Enter enable password: sanfran
The virtual terminal password used to protect the access to the router over a network interface.
Enter virtual terminal password: sanjose
Configure SNMP Network Management? [No]:
Configure IP? [Yes]:
Setup Interface Parameters
Configuring interface parameters:
Do you want to configure Ethernet 0 interface? [No]: Y
Configure IP on this interface? [No] Y
IP address for this interface: 10.1.1.33
Subnet mask for this interface [255.0.0.0]: 255.255.255.0
Class A network is 10.0.0.0. 245 subnet bits: mask is /24
Do you want to configure serial 0 interface? [No]:
Setup Script Review and Use
The following command script was created:
[0]Go to the IOS command prompt without saving this configuration
[1] Return back to the setup without saving this config
[2] Save this configuration to NVRAM and exit.
Enter your selection [2]:
What are the Basic Router Commands
Following are some of the router basic commands of user and privileged exec modes that are used for verifying, copying and deleting the configuration:
- Show version: To view the hardware and software status of the Cisco router
- Show flash: To view the files and directories reside in the flash of the Cisco router
- Show running-config: To view the status of RAM, the current configuration of the Cisco router
- Show startup-config: To view the status of NVRAM, the saved configuration of Cisco router
- Show interfaces: To view the detailed information about all the interfaces of the Cisco router
- Show ip interfaces: To view the detailed ip configuration on all the interfaces of the Cisco router
- Show interfaces serial 0: To view the detailed information about a specific interface of the Cisco router
- Show ip interfaces serial 0: To view the detailed IP configuration on a specific interface of the Cisco router
- Show ip interface brief: To view the brief ip configuration on all the interfaces of Cisco router
- Show line: To view the brief information about all the lines of the Cisco router
- Show line console 0: To view the detailed information about a specific line of the Cisco router
- Show user: To view some details about the users that are currently login on the Cisco router through any line.
- Show ip route: To view the IP routing table of the Cisco router
- Show ip protocols: To view the IP routing protocols that are currently running on the Cisco router
- Show history: To view the last ten IOS commands that were executed on the Cisco router
- Erase startup-config: To erase the contents of NVRAM of the Cisco router
- Erase Flash: To erase the contents of Flash of the Cisco router
- Copy running-config startup-config: To copy the contents of RAM into the NVRAM of the Cisco router
- Copy startup-config tftp: To copy the saved configurations from NVRAM into the TFTP server for backup purpose
- Copy flash tftp: To copy the IOS image file from Flash into the TFTP server for backup purpose
- Copy tftp startup-config: To restore the copy of saved configuration into NVRAM from the TFTP server
- Copy tftp flash: To restore the copy of IOS file image into Flash from the TFTP server
