Cisco Router password restoration experience

The Cisco router has a very high market demand. At the same time, users are not familiar with some features. Here we will introduce some questions about the Cisco Router password restoration for your reference.

How Cisco Router password is restored

1) The Cisco router stores several different configuration parameters and stores them in different memory modules. The memory of Cisco Series routers includes ROM, Flash memory, RAM, immutable RAM, and Dynamic memory DRAM. See table 1 ). Generally, when a vrodram starts, it first runs the program in ROM, conducts system self-check and boot, then runs the ISO in Flash, searches for vro configuration in NVRAM, and loads it into DRAM.

2) the key to restoring the Cisco Router password is to modify the Configuration Register Value in Table 2, so that the router can call different parameter tables from different memory to start. Valid passwords are stored in NVRAM. Therefore, the essence of the password modification is that the registration code does not work first, so that it can be started directly. After that, the registration code Cisco Router password can be restored if it is forgotten to be restored, the configuration modified after the vro is restarted may be lost ).

Memory Function

The boot program of the ROM storage system, similar to the BIOS of a PC, is a read-only memory. The system power-down program will not lose the flash memory to store the Cisco IOS image, similar to the hard disk of a PC, is a erasable, programmable ROM, the system power loss data will not lose NVRAM storage configuration file Startupconfig) RAM to store the current system using the configuration Runningconfig) DRAM mainly includes the route table, ARP cache, Fastswitch cache, and data packet cache. It also contains the configuration file in progress. If the system powers down, the memory data will be lost in Table 2Cisco series router configuration login code. There are different methods for Cisco routers to enter the rom status, but generally the following three methods can be used to enter the rom status. during use, you can try them separately.

1) if the Break is not blocked, press Ctrl + Break within 60 s to stop the startup process and enter the rom status.

2) If the Break key has been blocked, you can use the cycle Boot Method to enter the rom status. The method is: after the vro is started, the power supply is turned off and the instance is restarted after 5 seconds, generally, it enters the rom status. This method applies to vrouters such as 7500 and 12000.

3) set the baud rate of the Super Terminal to 1200, data bit 8, parity bit 1, stop bit none. Turn on the router power, shut down after startup, reboot after 5 s, and hold down the Space key for 12 s until the router is started, and then change the default value of the Super Terminal bit, the communication baud rate is set to 9600, the data bit is 8, the parity bit is 1, and the stop bit is 1. After the connection is reconnected, you can see from the terminal that it is in the rom status. Note: When the baud rate is 1200, NO content is displayed on the terminal. This method is applicable to vrouters 2500, 2600, And 4500.

Conclusion

As a layer-3 device, a router is a network device with a high technical level. It involves various protocols and has a wide technical scope. Skillful Use of various routers to timely handle various sudden failures is of great significance for maintaining the normal operation of the network. This article only introduces the password restoration methods for Cisco routers of typical models in Cisco Series routers. However, the specific operations for solving similar problems of Cisco Series routers are similar.