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Switch does not recognize user and password

IOS change was made to a switch 2960, from version 15.0 (2) to version 12.2 (55) as it presented problems for telnet access and console. However once made ​​the switch and boot the switch with the new image gives the error "Invalid encryption type: 4. Password not set", not recognizing any user . The switch is functioning normally, but without administration. Is there any way to enter without making password recovery?

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This is a quite interesting

This is a quite interesting issue. Perhaps it may help if we start by trying to understand what caused the issue and then we will consider how you might recover from it.


One of the things that Cisco wanted to do as they released version 15.0 was to improve the security of passwords in IOS. So they designed and implemented a new "type 4" password which they intended to replace the previous "type 5" password used for enable secret or for username secret passwords. So in those versions of 15.0 if you configure enable secret or username secret for passwords the IOS would create the new type 4 password.


Then you reacted to some problem and loaded an older version of IOS. 12.2(55) does not understand the type 4 passwords. So as your switch booted on this version of code and it read lines in the startup config that had type 4 passwords it did not understand them and marked them as invalid input. So the result is that your switch does not have an enable secret and perhaps usernames do not have passwords.


I do not know if you will be able to recover without doing password recovery but I have a suggestion which you can try. See if you can login on the console. It may depend on how your switch was configured whether it will let you do that and whether it will let you get to enable mode on the console. The default behavior was to allow the console to get to enable mode without a password. If your configuration includes aaa authentication enable default enable then the console may not work and in that case I believe that your only alternative will be password recovery.





Community Member

If you have SNMP configured

If you have SNMP configured you can get current configuration off of the switch and then modify the password.

Here is a link

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