Administration of Cisco devices
In this article I will demonstrate that how can you perform basic administrative task on Cisco devices.
Back Up and Restore IOS
You can use TFTP, FTP, or RCP to transfer an IOS image to or from a server. Only tftp server is covered in CCNA exam so we will cover it. TFTP is the trivial file transfer protocol. Unlike FTP, there are no means of authenticating with a username or password or navigating directories.
To back up your IOS, you will use the copy command from within privileged EXEC mode. The syntax of this command is copy . Thus, if you want to copy an IOS from your IOS to a TFTP server, the syntax would be copy tftp flash. After executing this command, you will be prompted with a number of questions asking for such things as the IOS filename and IP address of the TFTP server.
To restore or upgrade your IOS from a TFTP server to a router, the syntax would be copy tftp flash.
Remember the following troubleshooting steps if you are having difficulties using TFTP:
- Verify that the TFTP server is running.
- Verify cable configurations. You should use a crossover cable between a router and a server or, if you have a switch, use a straight-through cable from the router to the switch and from the switch to the server.
- Verify that your router is on the same subnet as your TFTP server.
- If you are using a Linux TFTP server, make sure that you first use the touch command to create a zero-byte file with the name of the IOS image; otherwise, the file will not copy to the TFTP server.
Being a Cisco Associate you should be able to take back and restore of networks critical resources. Cisco devices use Tftp server for this purpose. In real life you should keep daily back up of Cisco IOS and running configuration. In lab we can do the same practical on packet tracker.
Step by Step Guide to Back up and Restore of Network Devices
Download this topology and load it in packet tracer
As you can see in diagram we have a TFTP server connected with router from cross cable. A pc is connected with router from console cable. IP address on Server is 10.0.0.2 and 10.0.0.1 on routers fast Ethernet port 0/0 is already configured.
Now your task is to take the back of running configuration on tftp server. So we can retrieve it in any situations.
Double click on pc0 click on Desktop tab select terminal click on terminal configuration ( Do not change default setting). Click on ok This will emulate Router on screen
Now Follow these steps
R1>enable R1#copy running-config tftp: Address or name of remote host []? 10.0.0.2 Destination filename [R1-confg]? .!! [OK - 359 bytes] 359 bytes copied in 3.078 secs (0 bytes/sec) R1#
Now we have taken the backup of running configuration. To verify it click on Server and select config tab and click on TFTP and scroll down. At the end of window you can see the backup files
As you can see in image we have successfully taken the backup. Now open again terminal in PC0 and remove the startup configuration. And reload the router. R1>enable R1#erase startup-config Erasing the nvram filesystem will remove all configuration files! Continue? [confirm] [OK] Erase of nvram: complete %SYS-7-NV_BLOCK_INIT: Initialized the geometry of nvram R1#reload Proceed with reload? [confirm]
Now router will restart and as we have already discussed in our pervious article Booting process of Cisco devices, that router load its running configuration from NARAM. And we have deleted the contain for NAVRAM (Startup-configuration) so it will launch default startup program. Write No and press enter.
Now you will see default router prompt. We have to do some basic setting before connecting the TFTP Server. Router>enable Router#configure terminal Router(config)#interface fastethernet 0/0 Router(config-if)#ip address 10.0.0.1 255.0.0.0 Router(config-if)#no shutdown Router(config-if)#exit Router(config)#exit Router#
we have done the essential configuration to connect the tftp server. Now restore the configuration back to router Router#copy tftp running-config Address or name of remote host []? 10.0.0.2 Source filename []? R1-confg Destination filename [running-config]? Loading R1-confg from 10.0.0.2: ! [OK - 359 bytes] 359 bytes copied in 0.032 secs (11218 bytes/sec) R1#
At this point the configuration is in RAM so you will lost it on reboot so copy it in NVRAM. R1#copy running-config startup-config Destination filename [startup-config]? Building configuration... [OK] R1#
Step by step guide on How to update IOS
Being a CCNA certified associate you should also be capable to update the IOS of Cisco devices. This process include the serious risk of getting defective of device. So don’t do it on live device until you became perfect on simulator.Download this topology and load it in packet tracer
IP and other setting is already configured on Server and Router. We have new IOS stored on TFTP Server. Double click on pc0 click on Desktop tab select terminal click on terminal configuration ( Do not change default setting). This will emulate Router on screen. First step toward the updating of IOS is to check the available space in flash
R1>enable R1#sh flash System flash directory: File Length Name/status 1 33591768 c1841-advipservicesk9-mz.124-15.T1.bin [33591768 bytes used, 30424616 available, 64016384 total] 63488K bytes of processor board System flash (Read/Write) R1#
As you can see in output we have 30424616 bytes free available. We can download new IOS in flash from TFTP Server. To load new IOS R1#copy tftp flash Address or name of remote host []? 10.0.0.2 Source filename []? c1841-ipbasek9-mz.124-12.bin Destination filename [c1841-ipbasek9-mz.124-12.bin]? . Loading c1841-ipbasek9-mz.124-12.bin from 10.0.0.2: !!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! [OK - 16599160 bytes] 16599160 bytes copied in 5.989 secs (620180 bytes/sec)
As you can see in output we have downloaded new IOS now we can remove old IOS
R1#delete flash:c1841-advipservicesk9-mz.124-15.T1.bin Delete filename [c1841-advipservicesk9-mz.124-15.T1.bin]? Delete flash:/c1841-advipservicesk9-mz.124-15.T1.bin? [confirm] R1#show flash System flash directory: File Length Name/status 2 16599160 c1841-ipbasek9-mz.124-12.bin [16599160 bytes used, 47417224 available, 64016384 total] 63488K bytes of processor board System flash (Read/Write) R1#
Now restart the router to take effect of new IOS
R1#reload Proceed with reload? [confirm] %SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload Command. System Bootstrap, Version 12.3(8r)T8, RELEASE SOFTWARE (fc1) Cisco 1841 (revision 5.0) with 114688K/16384K bytes of memory. Self decompressing the image : ################################################################# [OK] Restricted Rights Legend Cisco IOS Software, 1841 Software (C1841-IPBASEK9-M), Version 12.4(12), Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2006 by Cisco Systems, Inc. Compiled Mon 15-May-06 14:54 by pt_team Image text-base: 0x600790EC, data-base: 0x61480000 Cisco IOS Software, 1841 Software (C1841-IPBASEK9-M), Version 12.4(12), Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2006 by Cisco Systems, Inc. Compiled Mon 15-May-06 14:54 by pt_team --- System Configuration Dialog --- Continue with configuration dialog? [yes/no]: no Press RETURN to get started! Router>
As you can see in output router is booted from new IOS. As new IOS is loaded so all pervious configuration will also be removed load it again from TFTP Server and save it to NVRAM.
Other Useful administrative commands
no ip domain-lookup
Router(config)#no ip domain-lookupEver type in a command incorrectly and are left having to wait for a minute or two as the router tries to translate your command to a domain server of 255.255.255.255? The router is set by default to try to resolve any word that is not a command to a Domain Name System (DNS) server at address 255.255.255.255. If you are not going to set up DNS, turn off this feature to save you time as you type, especially if you are not good in typing.
logging synchronous
Router(config)#line console 0 Router(config-line)#logging synchronous Router(config-line)#exit Router(config)#Some time it happens that you are typing a command and an informational line appears in the middle of what you were typing? Lose your place? Do not know where you are in the command, so you just press R and start all over? The logging synchronous command tells the router that if any informational items get displayed on the screen, your prompt and command line should be moved to a new line, so as not to confuse you. The informational line does not get inserted into the middle of the command you are trying to type. If you were to continue typing, the command would execute properly, even though it looks wrong on the screen.
exec-timeout
Router(config)#line console 0 Router(config-line)#exec-timeout 0 0 Router(config-line)#The command exec-timeout 0 0 is great for a lab environment because the console never logs out. This is considered to be bad security and is dangerous in the real world. The default for the exec-timeout command is 10 minutes and zero (0) seconds (exec-timeout 10 0).
erase startup-config
Router#erase startup-configSome time you want to reconfigure the router. Or want to sell the old one. In such a scenario you would like to erase the start up configuration. The running configuration is still in dynamic memory. Reload the router to clear the running configuration.
do Command
Router(config)#do show running-configThe do command is useful when you want to execute EXEC commands, such as show, clear, or debug, while remaining in global configuration mode or in any configuration submode. You cannot use the do command to execute the configure terminal command because it is the configure terminal command that changes the mode to global configuration mode
Summary of Useful commands for administrations
| Router(config)#boot system flash imagename | Loads the Cisco IOS Software with image-name |
| Router(config)#boot system tftp image-name 172.16.10.3 | Loads the Cisco IOS Software with image-name from a TFTP server |
| Router(config)#boot system rom | Loads the Cisco IOS Software from ROM. |
| Router(config)#exit | exit from global configurations |
| Router#copy running-config startup-config | Saves the running configuration to NVRAM. The router will execute commands in their order on the next reload. |
| Router#copy running-config startup-config | Saves the running configuration from DRAM to NVRAM (locally). |
| Router#copy running-config tftp | Copies the running configuration to the remote TFTP server |
| Address or name of remote host[ ]? 192.168.1.20 | The IP address of the TFTP server. Press Enter key |
| Destination Filename [Router-confg]? | The name to use for the file saved on the TFTP server Press Enter key |
| !!!!!!!!!!!!!!! | Each bang symbol (!) = 1 datagram of data. |
| 624 bytes copied in 7.05 secs | |
| Router# | File has been transferred successfully |
| Router#copy tftp running-config | Copies the configuration file from the TFTP server to DRAM. |
| Address or name of remote host[ ]? 192.168.119.20 | The IP address of the TFTP server. |
| Source filename [ ]?Router-confg | Enter the name of the file you want to retrieve |
| Destination filename [running-config]? | Press Enter key |
| Router# | File has been transferred successfully. |
| Router#copy flash tftp | Backup of flash to tftp |
| Router#copy tftp flash | Restore flash from tftp server |
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