Monitoring Your Network - Getting Started with NerveCenter Client - Setting Up Alarm-Instance Filters - Filtering Alarms by IP Range -
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Filtering Alarms by IP Range

When you filter alarms by IP range, you are specifying that you only want to display alarm instances in the NerveCenter Client from particular nodes identified by their IP addresses.

See IP Subnet Filter Exclusion Rules, for more information about filtering alarms by IP ranges.

Although you can create a filter simply based on an IP range, a single filter can contain any combination of:

• A list of subnets
• A list of severities
• A list of property groups

For information on how to build an alarm-instance filter based on severities and property groups, see the respective section listed below:

• Filtering Alarms by Severity
• Filtering Alarms by Property Groups

 
  To create an alarm filter based on an IP range:

1. Choose Configuration from the Client menu.

   The Client Configuration dialog is displayed.

   Client Configuration Dialog

   

2. Select the Alarm Filter Modification tab.

   The Alarm Filter Modification page is displayed.

   Alarm Filter Modification Page

   

3. Select the New button.

   The Alarm Filter Definition dialog is displayed.

   Alarm Filter Definition Dialog

   

   This is the dialog you use to define your filter.

4. If you want to filter alarm instances based on the IP addresses of the alarm instances' nodes, perform the steps below for each subnet you want to be part of the filter. That is, you want to see information about instances whose nodes have IP addresses on these subnets.
   1. Enter an IP address in the Subnet text field.

      The IP address must consist of four octets separated by periods.

   2. Enter a subnet mask in the Mask text field.

      The subnet mask must consist of four octets separated by periods. Taken together with the subnet address, this mask defines the subnet whose nodes you're monitoring.

   3. In the Exclusion text field, enter the last octet of the IP address of any node on the subnet that you're not monitoring.

      You can enter multiple exclusions separated by commas. You can also enter a range of excluded nodes using a hyphen. For example, if you enter 24, 76-78 in the Exclusion field, the nodes whose addresses end in 24, 76, 77, and 78 will be excluded by the filter.

   4. Select the Add button.
   5. Repeat step a to step d to add other subnets to the alarm filter.
5. Enter a name for your filter in the Filter Name field.
6. Select the OK button.

   The Alarm Filter Definition dialog is closed and you return to the Client Configuration dialog box.

You've now defined an alarm filter based on an IP range. Before the client will use the filter, however, you must associate the filter with a server. For instructions on how to create this association, see the section Associating a Filter with a Server.

IP Subnet Filter Exclusion Rules

When you filter by subnet, you specify which subsets of nodes are managed by NerveCenter. Filtering does not apply to nodes that have been imported from a file or from another NerveCenter. For an example, see IP Subnet Filter Examples.

You can exclude specific nodes that belong to the filter by entering an exclusion. To exclude one or more nodes, you must specify the full subnet and mask, and then enter the individual nodes you want excluded. Enter the part of the IP address that is not affected by the subnet's mask.

NerveCenter filters Class B and C networks.

Class C Networks

In a Class C network, the first three octets of the address specify the network and the last octet specifies the host. For example, in network 194.123.45.0, the 194.123.45 value pertains to the network. The remaining octet is used to identify nodes (up to 254) on the network, and you can exclude nodes by specifying ID values in this octet.

Class B Networks

For a Class B network, only the first two octets of the address specify the network. For example, in network 132.45.0.0, the 132.45 value pertains to the network. The remaining two octets are used to identify nodes, and you can exclude nodes by specifying ID values in these two octets.

Example

In the following example, the node whose IP address is 134.204.179.40 is excluded from the filter (the node is filtered out and, therefore, is not managed by NerveCenter).

Rules for Exclusions

• You can enter several nodes separated by a comma. NerveCenter accepts comma-separated values with or without spaces following the commas. You can enter the node values in any order.

  The following three examples (each on a separate line) illustrate valid exclusions:

  
     7,8,9,15
   7, 8, 9, 15
   8,7,9,15
• You can enter a range of values using a hyphen.

  For example, you can enter as an exclusion range: 40-60

  You can also enter the range in inverse order: 60-40

• You can include multiple entries for the same subnet if you have values or ranges that are not incremental.
  • For example, you can enter as a filter:
       134.204.179.0
   255.255.255.0
   7,8,9
   134.204.179.0
   255.255.255.0
   40-60
   134.204.179.0
   255.255.255.0
   70-90
  • You can combine ranges, for example:
       134.204.179.0
   255.255.255.0
   40-60,70-90
  • You can also combine formats, for example:
       134.204.179.0
   255.255.255.0
   7-9,31,33,40-60

IP Subnet Filter Examples

The following examples can help you understand how to filter nodes for Class B and C networks.

Class C Network

The following subnet filters are for two sample nodes:

• Sample node #1 with IP address: 197.204.179.25
• Sample node #2 with two IP addresses:
  • 134.204.179.40
  • 197.204.179.7

The filter values in the table below have the following effects on the sample nodes:

Class C Network Examples

Class B Filters

The following subnet filters are for two sample nodes:

• Sample node #1 with IP address: 132.45.160.10
• Sample node #2 with IP address: 132.45.174.10

The mask you use for this filter is 255.255.0.0.

Class B Filter Examples (Set One)

If you use a subnet mask of 255.255.240.0, you would get different results.

• Sample node #1 with IP address: 132.45.160.10
• Sample node #2 with IP address: 132.45.174.10

You must first apply the filter before determining the node's ID. The filter values in the table below have the following effects:

Class B Filter Examples (Set Two)