Troubleshooting

Unusual Network Activity

A key in the file is too long. The maximum key length is 1024 characters, including spaces. This could also mean that two or more keys are merged together instead of being separated by a <CR><LF>.

There are more than ten public keys in the key file.

One or more keys in the file is corrupted or is not a valid rsa public key.

Client ceases to respond (“hangs”) during connection phase. The switch does not support data compression in an SSH session. Clients will often have compression turned on by default, but will disable it during the negotia­ tion phase. A client which does not recognize the compression-request FAIL­ URE response may fail when attempting to connect. Ensure that compression is turned off before attempting a connection to prevent this problem.

TACACS-Related Problems

Event Log. When troubleshooting TACACS+ operation, check the switch’s Event Log for indications of problem areas.

All Users Are Locked Out of Access to the Switch. If the switch is func­ tioning properly, but no username/password pairs result in console or Telnet access to the switch, the problem may be due to how the TACACS+ server and/or the switch are configured. Use one of the following methods to recover:

Access the TACACS+ server application and adjust or remove the configuration parameters controlling access to the switch.

If the above method does not work, try eliminating configuration changes in the switch that have not been saved to flash (boot-up configuration) by causing the switch to reboot from the boot-up configuration (which includes only the configuration changes made prior to the last write memory command.) If you did not use write memory to save the authentication configuration to flash, then pressing the Reset button or cycling the power reboots the switch with the boot-up configuration.

Disconnect the switch from network access to any TACACS+ servers and then log in to the switch using either Telnet or direct console port access. Because the switch cannot access a TACACS+ server, it will default to local authentication. You can then use the switch’s local Operator or Manager username/password pair to log on.

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