Excluding specific parts of configuration from comparison in the NCM

Configuration files store critical information like interface configurations, router configurations, ACLs, security configurations, QoS policies, VLAN configurations, infrastructure and application settings, and other device management settings that define a device's behavior within a network. They help manage various network parameters and customize your networks.

Site24x7's Network Configuration Manager (NCM) sends alerts if there is any change in the configuration file based on the threshold configuration. Additionally, you can also view if there are conflicts between any versions of the startup and running configurations.

However, some changes can be ignored based on your discretion. For instance, there might be commented lines or encrypted password strings (which may change for each configuration

 version) that could be causing repeated alerts, even though there are no other changes in the configuration file.

To understand this, compare configurations or different versions to see all the differences between them.

Assume there's a change in the current running configuration. If there's a threshold profile that checks for any change in the running configurations, it can lead to alerts being generated and unexpected changes in the status of a device. Figure 1 illustrates such differences, which may result in the device's status being set to Down, Trouble, or Critical, depending on the settings specified in the threshold profile (an example is shown in Figure 2).

Figure 1. Configuration differences between startup and running versions.

Additionally, you will also be able to see conflicts on the Monitor Status screen.

To exclude differences from comparison, Site24x7's NCM uses regular expressions.

What are regular expressions?  

A regular expression is used to check for matches in a search based on a sequence of patterns.

Here are some common expressions that you can use to create the regular expression that you require:

The following table describes a few regular expressions with examples: 

Other common regular expressions:

You can use our Regex Tester and Debugger Tool to validate regular expression patterns. 

To modify the criteria to exclude specific content during configuration comparison

1. Log in to your Site24x7 account.
   
2. Navigate to Network > NCM > Device Templates.
3. Click the device template for which you wish to set the exclude criteria to view the details. 
   
   
   Figure 2. Device Templates screen. 
4. Click Exclude Criteria. You will see the default excluded criteria provided in the device template and custom criteria if it has been added already. Close the Exclude Criteria pop-up to go back to the Device Template details screen.
   
5. To add, edit, or delete custom criteria, click Edit Device Template in the top-right of the screen. Alternatively, you can click the pencil icon beside the appropriate device template in the third step (Figure 4, marked in blue).
6. Then, click Exclude Criteria. You can edit any existing custom criteria here by modifying the details in the editable fields.
7. Click the X icon beside the Description column to delete a previously added criterion.

To add a new criterion

1. Click Exclude Criteria on the Edit Device Template screen.
2. Enter the details in a row with blank fields. Or, to add more than one criterion, click the plus + icon.
3. Provide a display name.
4. Next, provide the regular expression pattern in the RegEx column. For example, if you wish to exclude the statements speed and Current configuration in Figure 1 from showing up in differences, you can provide the pattern to exclude it as shown in Figure 3. 
   
   
   Figure 3. Device Templates screen. 
5. Provide details in the Description column.
   
6. Click Save.
   
   Figure 4. Comparing configurations after adding excluded criteria.

Related Articles

• Site24x7's NCM
• NCM device templates
• NCM credentials
• NCM Configuration Summary

Troubleshooting Tips

• Troubleshooting issues with Site24x7's NCM