NCM login failure on CATOS devices when authentication is handled via TACACS

10/8/2018 8:28 PM

10/9/2018 6:04 PM

Network Configuration Manager (NCM) requires devices to respond and behave within certain pre-set/expected parameters in order to connect. Login/password prompts and device prompts are the most important. There are some cases in which ASCII characters are appended to the prompt hostname> when connecting for the first time, and then the actual prompt is sent to NCM. But subsequent prompt appearances are changed, and resemble the following example: hostname> (enable). This article provides a possible workaround for this behavior.

Network Configuration Manager

The problem occurs when the device sends the initial Hostname and the prompt has extra characters appended to the returned prompt. NCM sets the matching criteria to determine when to start and stop processing data, but as subsequent returns of the prompt are normal and differ from the original, NCM does not match them and times out waiting for a match. 

Note: Verify that the device is returning a prompt with the extra characters. (They are generally ASCII.)
Check this by turning on session tracing or when testing the login via the edit node properties, click the Show credential login details: slowly scroll through the output. If the first time the prompt is sent it contains extra characters, this issue is present.

Use the same login information for the show login credential login details to determine the Device template NCM is using if you have not manually set it. The Device Template is at the top of the output. Copy this template and make a modification for this device to use. Follow these these instructions to gain access: Modify a default device template in NCM 7.4

For the intent of this article, the commands in the template should be the following to login and download a config if the the CATOS device is exhibiting this issue. They should not be used as a standard NCM Device Template.

<Commands>        
<Command Name="RESET" Value="set length 0"/>        
<Command Name="Reboot" Value="reload${CRLF}y${CRLF}y"/>        
<Command Name="EnterConfigMode" Value=""/>        
<Command Name="ExitConfigMode" Value=""/>        
<Command Name="Startup" Value="config"/>        
<Command Name="Running" Value="config"/>        
<Command Name="DownloadConfig" Value="show config"/>        
<Command Name="UploadConfig" Value="${EnterConfigMode}${CRLF}${ConfigText}${CRLF}${ExitConfigMode}"/>        
<Command Name="DownloadConfigIndirect" Value="copy ${ConfigType} ${TransferProtocol}://${StorageAddress}/

${StorageFilename}${CRLF}${CRLF}${CRLF}"/>        
<Command Name="UploadConfigIndirect" Value="copy ${TransferProtocol}://${StorageAddress}/${StorageFilename}  

${ConfigType}${CRLF}${CRLF}"/>        
<Command Name="EraseConfig" Value="write erase${CRLF}Y"/>        
<Command Name="SaveConfig" Value="write memory"/>        
<Command Name="Version" Value="show version"/>                           
<Command Name="EnableIdentifier" Value="(enable)"/>
<Command Name="PreCommand" Value="${CRLF}"/>

</Commands>

Manually assign your new template to the device(s) with the problem, and do not set the device Template to be used for Auto determine unless all of the like devices have this issue.