For obtaining the version, you can generally download it through the website or contact the supplier to provide it. You can also use regular commands to back up the version to the server when the router is working normally for emergency purposes. There are many types of CISCO routers, and the password recovery and disaster recovery of various routers are different. We will describe them separately.
one. 2500 series routers (taking 2509 as an example)
1. Password recovery
1.1 Use the DB25 conversion interface and the cross-line to connect the CONSOLE port of the 2509 router to the computer serial port, start the computer hyperterminal, set its parameters to baud rate 9600, data bit 8, parity to None, stop bit 1, and flow control select None. Turn on the router power, press ctlr+break within 60 seconds of power-on to make the router enter the rom monitor state, prompt >
1.2 Check the configure –register value and record the value.
>e/s2000002
When the return value is normal, it is generally 2102
1.3 Update the configuration-register value to make the router skip the configuration file when starting and start directly so that the original password does not work.
>o/r0x0142
1.4 Restart the router>i
1.5 Enter privileged mode after startup and execute the following command to make the original configuration information valid.
router(config)#config mem
1.6 You can view the original password according to normal operations or modify it to a new password.
1.7 Restore the configure-register value and restart the router. This will restore normality.
Router(config)#configure-register 0x2102
Router(config)#wri
Router(config)#reload
2. Version catastrophic recovery
Unlike other routers, 2509 has a boot monitoring mode inside rom, which contains a small image version. When the version in flash is corrupted, it can be used for official version downloads.
2.1 While connecting the computer serial port and the 2509CONSLOE port, a conversion interface between AUI and RJ45 must be prepared so that the AUI port can be connected to the computer network port using a cross-wire.
2.2 In boot monitoring mode, enter privileged mode and configure the interface address and mask of the Ethernet port to make it on the same subnet as the computer network port address (assuming that the computer address bit 168.1.32.206 255.255.0.0 Router Ethernet address bit 168.1.32.207 255.255.0.0)
router(boot)#config t
router(boot)(config)#int ethernet 0
router(boot)(config-if)#ip address 168.1.32.207 255.255.0.0
2.3 Verify network interoperability
router(boot)#ping 168.1.32.206
2.4 Start the tftp server on the computer and place the version you need to download in the specified directory of the server.
2.5 Execute the following command on the hyper terminal:
router(boot)#copy tftp flash
Download the new version to the router's flash,
2.6 Restart the router and run the new normal version
router(boot)#reload
two. 2600 series (taking 2621 as an example)
1. Password recovery
1.1 Connect the CONSOLE port of the router to the computer serial port, start the computer hyper terminal, turn on the router power, press ctlr+break within 60 seconds of power-on to make the router enter the rom monitor state, prompt
rommon1>
1.2 Reconfigure the configuration register
rommon1>confreg
When do you wish to change the configuration (y/n) appears, select y
Select the next option n
When enable "ignore system configuration information" (y/n) appears, select y
Select the next option n
1.3 Restart the router
rommon1>reset
1.4 Enter privileged mode after startup and execute the following command to make the original configuration information valid.
router(config)#config mem
1.5 You can further view the password or change the password
2. Version of the catastrophic recovery
2621 provides two methods for catastrophic recovery versions, tftpdnld and xmodem methods.
2.1 tftpdnld method
2.1.1 Connect the computer serial port and the router CONSLE port, and connect the computer network port to the router Ethernet port (must be connected to the first Ethernet port)
2.1.2 Start the TFTP server and place the version to be downloaded in the specified directory.
2.1.3 Turn on the router power supply. Since there is no valid version, the router will directly enter monitoring mode after starting.
Rommon1>
2.1.4 Set parameters according to the following command.
Rommon2>IP_ADDRESS=168.1.32.207
Rommon3>IP_SUBNET_MASK=255.255.0.0
Rommon4>DEFAULT_GATEWAY=168.1.32.206
Rommon5>TFTP_FILE=c2600-i-mz.
Rommon6>tftpdnld
The above assumes that the computer address is 168.1.32.206 255.255.0.0, command IP_ADDRESS=168.1.32.207
In monitoring mode, configure the 168.1.32.207 address to the first Ethernet port of the router, thereby establishing a connection between the router and the TFTP server and downloading the version normally.
2.1.5 Configuring the configuration register
Rommon7>confreg
When do you wish to change the configuration ?y/n select y
Other options n
When change the boot charaterist appears ?y/n select y
Select parameter 2
2.1.6 startup version
Rommon8> reset
2.2 xmodem download
This method does not require an Ethernet cable, just a hyper-terminal. The disadvantage is that it takes too much time and is too slow. Xmodem is an asynchronous file transfer protocol widely used in personal computer communications. It transmits data in the form of 128-byte blocks, and each block is verified. If the recipient is verified correctly, it sends the recognition information and the sender sends the next block. Ymodem asynchronous transmission protocol, the transmission word size is 1024, adding batch processing function.
2.2.1 After connecting to the router with the hyper terminal, start the router and the router enters the monitoring mode state.
Rommon1>
2.2.2 Start the xmodem command
Rommon2>xmodem –cx? Typ enter key
When do you wish to continous appears, select y
2.2.3 Open the "Transfer" menu of the hyper terminal and select Transfer Files to open the Transfer Files window.
Enter the location of the version file and select the xmodem method. After confirming, after a few seconds, the version file will be downloaded from the computer to the router in the form of xmodem.
Modify the corresponding commands and options, and can also be transmitted in ymodem.
2.2.4 Configure the confreg command in the same way as above. After restarting, the router will enter a normal state.
three. Password and version recovery of 3600 series routers (take 3640 as an example)
1. Password recovery
The password recovery of 3640 is basically similar to that of 26 series. Both enter monitoring mode, run the confreg command, ignore the configuration file when starting, and start it directly. This method also works for 4500 7500 12000 series routers.
2. Version recovery
The 3640 version recovery does not provide the tftpdnld command, but only the xmodem command is provided, and the usage method is the same as that in the 26 series.
Four. Several ways to enter ROM state
The methods for various cisco routers to enter the rom state are different, but generally the following three methods can be used to enter the rom state, and you can try to enter separately during use.
4.1 If break is not blocked, press the ctl+break key within 60 seconds of starting the machine to interrupt the startup process and enter the rom state.
4.2 If the break key is blocked, you can enter the rom state by cycling startup.
The method is: after the router is turned on, turn off the power. If the power is restarted after 5 seconds, it will usually enter the rom state. This method is suitable for routers such as 7500 12000.
4.3 Set the hyperterminal communication baud rate to 1200, the data bit is 8, and the parity bit is 1 stop bit is none. Turn on the router power, and shut down after starting. After stopping for 5 seconds, restart the power, hold down the space bar for 12 seconds and then release it. After the router starts up, change the default value of the hyper terminal bit again. The communication baud rate is set to 9600, the data bit is 8, and the parity bit is 1 stop bit is none. After reconnecting, you can see from the terminal that you have entered the rom state. Note that when the baud rate is 1200, there is no content displayed on the terminal. This method is suitable for 2500, 2600, 4500 and other series of routers
5 Conclusion
As a layer three device, routers play the role of finding routes in the network, but routers are also a network device with high technical content. They involve various protocols and have a wide range of technical aspects. Proficient in using various routers and promptly dealing with various sudden failures is of great significance to maintaining the normal operation of the network. Through a relatively comprehensive summary, this article summarizes the password and version recovery methods of common routers, which has a certain guiding role in dealing with common similar problems.
, Article entry: csh Editor in charge: csh
one. 2500 series routers (taking 2509 as an example)
1. Password recovery
1.1 Use the DB25 conversion interface and the cross-line to connect the CONSOLE port of the 2509 router to the computer serial port, start the computer hyperterminal, set its parameters to baud rate 9600, data bit 8, parity to None, stop bit 1, and flow control select None. Turn on the router power, press ctlr+break within 60 seconds of power-on to make the router enter the rom monitor state, prompt >
1.2 Check the configure –register value and record the value.
>e/s2000002
When the return value is normal, it is generally 2102
1.3 Update the configuration-register value to make the router skip the configuration file when starting and start directly so that the original password does not work.
>o/r0x0142
1.4 Restart the router>i
1.5 Enter privileged mode after startup and execute the following command to make the original configuration information valid.
router(config)#config mem
1.6 You can view the original password according to normal operations or modify it to a new password.
1.7 Restore the configure-register value and restart the router. This will restore normality.
Router(config)#configure-register 0x2102
Router(config)#wri
Router(config)#reload
2. Version catastrophic recovery
Unlike other routers, 2509 has a boot monitoring mode inside rom, which contains a small image version. When the version in flash is corrupted, it can be used for official version downloads.
2.1 While connecting the computer serial port and the 2509CONSLOE port, a conversion interface between AUI and RJ45 must be prepared so that the AUI port can be connected to the computer network port using a cross-wire.
2.2 In boot monitoring mode, enter privileged mode and configure the interface address and mask of the Ethernet port to make it on the same subnet as the computer network port address (assuming that the computer address bit 168.1.32.206 255.255.0.0 Router Ethernet address bit 168.1.32.207 255.255.0.0)
router(boot)#config t
router(boot)(config)#int ethernet 0
router(boot)(config-if)#ip address 168.1.32.207 255.255.0.0
2.3 Verify network interoperability
router(boot)#ping 168.1.32.206
2.4 Start the tftp server on the computer and place the version you need to download in the specified directory of the server.
2.5 Execute the following command on the hyper terminal:
router(boot)#copy tftp flash
Download the new version to the router's flash,
2.6 Restart the router and run the new normal version
router(boot)#reload
two. 2600 series (taking 2621 as an example)
1. Password recovery
1.1 Connect the CONSOLE port of the router to the computer serial port, start the computer hyper terminal, turn on the router power, press ctlr+break within 60 seconds of power-on to make the router enter the rom monitor state, prompt
rommon1>
1.2 Reconfigure the configuration register
rommon1>confreg
When do you wish to change the configuration (y/n) appears, select y
Select the next option n
When enable "ignore system configuration information" (y/n) appears, select y
Select the next option n
1.3 Restart the router
rommon1>reset
1.4 Enter privileged mode after startup and execute the following command to make the original configuration information valid.
router(config)#config mem
1.5 You can further view the password or change the password
2. Version of the catastrophic recovery
2621 provides two methods for catastrophic recovery versions, tftpdnld and xmodem methods.
2.1 tftpdnld method
2.1.1 Connect the computer serial port and the router CONSLE port, and connect the computer network port to the router Ethernet port (must be connected to the first Ethernet port)
2.1.2 Start the TFTP server and place the version to be downloaded in the specified directory.
2.1.3 Turn on the router power supply. Since there is no valid version, the router will directly enter monitoring mode after starting.
Rommon1>
2.1.4 Set parameters according to the following command.
Rommon2>IP_ADDRESS=168.1.32.207
Rommon3>IP_SUBNET_MASK=255.255.0.0
Rommon4>DEFAULT_GATEWAY=168.1.32.206
Rommon5>TFTP_FILE=c2600-i-mz.
Rommon6>tftpdnld
The above assumes that the computer address is 168.1.32.206 255.255.0.0, command IP_ADDRESS=168.1.32.207
In monitoring mode, configure the 168.1.32.207 address to the first Ethernet port of the router, thereby establishing a connection between the router and the TFTP server and downloading the version normally.
2.1.5 Configuring the configuration register
Rommon7>confreg
When do you wish to change the configuration ?y/n select y
Other options n
When change the boot charaterist appears ?y/n select y
Select parameter 2
2.1.6 startup version
Rommon8> reset
2.2 xmodem download
This method does not require an Ethernet cable, just a hyper-terminal. The disadvantage is that it takes too much time and is too slow. Xmodem is an asynchronous file transfer protocol widely used in personal computer communications. It transmits data in the form of 128-byte blocks, and each block is verified. If the recipient is verified correctly, it sends the recognition information and the sender sends the next block. Ymodem asynchronous transmission protocol, the transmission word size is 1024, adding batch processing function.
2.2.1 After connecting to the router with the hyper terminal, start the router and the router enters the monitoring mode state.
Rommon1>
2.2.2 Start the xmodem command
Rommon2>xmodem –cx? Typ enter key
When do you wish to continous appears, select y
2.2.3 Open the "Transfer" menu of the hyper terminal and select Transfer Files to open the Transfer Files window.
Enter the location of the version file and select the xmodem method. After confirming, after a few seconds, the version file will be downloaded from the computer to the router in the form of xmodem.
Modify the corresponding commands and options, and can also be transmitted in ymodem.
2.2.4 Configure the confreg command in the same way as above. After restarting, the router will enter a normal state.
three. Password and version recovery of 3600 series routers (take 3640 as an example)
1. Password recovery
The password recovery of 3640 is basically similar to that of 26 series. Both enter monitoring mode, run the confreg command, ignore the configuration file when starting, and start it directly. This method also works for 4500 7500 12000 series routers.
2. Version recovery
The 3640 version recovery does not provide the tftpdnld command, but only the xmodem command is provided, and the usage method is the same as that in the 26 series.
Four. Several ways to enter ROM state
The methods for various cisco routers to enter the rom state are different, but generally the following three methods can be used to enter the rom state, and you can try to enter separately during use.
4.1 If break is not blocked, press the ctl+break key within 60 seconds of starting the machine to interrupt the startup process and enter the rom state.
4.2 If the break key is blocked, you can enter the rom state by cycling startup.
The method is: after the router is turned on, turn off the power. If the power is restarted after 5 seconds, it will usually enter the rom state. This method is suitable for routers such as 7500 12000.
4.3 Set the hyperterminal communication baud rate to 1200, the data bit is 8, and the parity bit is 1 stop bit is none. Turn on the router power, and shut down after starting. After stopping for 5 seconds, restart the power, hold down the space bar for 12 seconds and then release it. After the router starts up, change the default value of the hyper terminal bit again. The communication baud rate is set to 9600, the data bit is 8, and the parity bit is 1 stop bit is none. After reconnecting, you can see from the terminal that you have entered the rom state. Note that when the baud rate is 1200, there is no content displayed on the terminal. This method is suitable for 2500, 2600, 4500 and other series of routers
5 Conclusion
As a layer three device, routers play the role of finding routes in the network, but routers are also a network device with high technical content. They involve various protocols and have a wide range of technical aspects. Proficient in using various routers and promptly dealing with various sudden failures is of great significance to maintaining the normal operation of the network. Through a relatively comprehensive summary, this article summarizes the password and version recovery methods of common routers, which has a certain guiding role in dealing with common similar problems.
, Article entry: csh Editor in charge: csh