<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: SNMP Cisco ASA VPN Traffic Sensor

The SNMP Cisco ASA VPN Traffic sensor monitors the traffic of an Internet Protocol Security (IPsec) Virtual Private Network (VPN) connection on a Cisco Adaptive Security Appliance using Simple Network Management Protocol (SNMP).

It shows the following:

  • Incoming traffic
  • Outgoing traffic
     
SNMP Cisco ASA VPN Traffic Sensor

SNMP Cisco ASA VPN Traffic Sensor

Click here to enlarge: http://media.paessler.com/prtg-screenshots/snmp_cisco_asa_vpn_traffic.png

Remarks

Add Sensor

The Add Sensor dialog appears when adding a new sensor on a device manually. It only shows the setting fields that are imperative for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.

Select the connections you want to monitor. PRTG creates one sensor for each connection you select in the Add Sensor dialog. The settings you make in this dialog are valid for all of the sensors that are created.

The following settings for this sensor differ in the 'Add Sensor' dialog in comparison to the sensor's settings page:

ASA VPN Specific

Connections

Select the IPsec VPN connections you want to add a sensor for. You see a list with the names of all items which are available to monitor. Select the desired items by adding check marks in front of the respective lines. PRTG creates one sensor for each selection. You can also select and deselect all items by using the check box in the table head.

Note: This sensor type can only monitor VPN connections based on IPsec. This means, for example, that connections using "Cisco AnyConnect" are not listed here.

Sensor Settings

On the details page of a sensor, click on the Settings tab to change its settings.

Note: Usually, a sensor connects to the IP Address or DNS Name of the parent device on which you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. Please see below for details on available settings.

Basic Sensor Settings

Sensor Name

Enter a meaningful name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets.

Parent Tags

Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here.

Tags

Enter one or more Tags, separated by space or comma. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value.

You can add additional tags to it, if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.

Priority

Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).

ASA VPN Specific

Remote IP

Shows the IP address of the connection this sensor monitors. This value is shown for reference purposes only. We strongly recommend that you only change it if Paessler support explicitly asks you to do so for debugging. Wrong usage can result in incorrect monitoring data!

Note: This sensor type can only monitor VPN connections based on IPsec.

Sensor Behavior

Define the status of the sensor if there is no active connection available. Choose between:

  • Show 'Down' status if no connection is active (recommended)
  • Show 'Warning' status if no connection is active
  • Stay in 'Up' status if no connection is active

Sensor Display

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel will always be displayed below the sensor's name. The available options depend on what channels are available for this sensor. Note: You can set another primary channel later by clicking on the pin symbol of a channel in the sensor's Overview tab.

Chart Type

Define how different channels will be shown for this sensor.

  • Show channels independently (default): Show an own graph for each channel.
  • Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This will generate an easy-to-read graph which visualizes the different components of your total traffic. Note: This option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channels Settings settings).

Stack Unit

This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked on top of each other. By default, you cannot exclude single channels from stacking, if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings. To change a setting only for this object, disable inheritance by clicking on the check mark before the corresponding setting name. You will then see the options described below.

Credentials for SNMP Devices

SNMP Version

Select the SNMP version for the device connection. Choose between:

  • v1: Use the simple standard v1 protocol for SNMP connections. This protocol only offers clear-text data transmission, but it is usually supported by all devices.
  • v2c: Use the more advanced v2c protocol for SNMP connections. Data is still transferred as clear-text, but it supports 64-bit counters.
  • v3: Use the latest v3 protocol for SNMP connections. It provides secure authentication and data encryption.

Note for SNMP v3: Due to internal limitations you can only monitor a limited number of sensors per second using SNMP v3. The limit is somewhere between 1 and 50 sensors per second (depending on the SNMP latency of your network). This means that using an interval of 60 seconds you are limited to between 60 and 3000 SNMP v3 sensors for each probe. If you experience an increased "Interval Delay" or "Open Requests" with the Probe Health Sensor, you need to distribute the load over multiple probes. SNMP v1 and v2 do not have this limitation.

Community String

This setting is only visible if you select SNMP version v1 or v2c above. Enter the community string of your devices. This is a kind of "clear-text password" for simple authentication. We recommend that you use the default value.

Authentication Type

This setting is only visible if you select SNMP version v3 above. Choose between:

  • MD5: Use Message-Digest Algorithm 5 (MD5) for authentication.
  • SHA: Use Secure Hash Algorithm (SHA) for authentication.

The type you choose must match the authentication type of your device.

Note: If you do not want to use authentication, but you need SNMP v3, for example, because your device requires context, you can leave the field password empty. In this case, SNMP_SEC_LEVEL_NOAUTH is used and authentication deactivated entirely.

User

This setting is only visible if you select SNMP version v3 above. Enter a username for secure authentication. This value must match the username of your device.

Password

This setting is only visible if you select SNMP version v3 above. Enter a password for secure authentication. This value must match the password of your device.

Encryption Type

This setting is only visible if you select SNMP version v3 above. Select an encryption type. Choose between:

  • DES: Use Data Encryption Standard (DES) as encryption algorithm.
  • AES: Use Advanced Encryption Standard (AES) as encryption algorithm. Note: AES 192 and AES 256 are not supported by Net-SNMP because they lack RFC specification.

The type you choose must match the encryption type of your device.

Data Encryption Key

This setting is only visible if you select SNMP version v3 above. Enter an encryption key here. If you provide a key in this field, SNMP data packets are encrypted using the encryption algorithm selected above, which provides increased security. The key that you enter here must match the encryption key of your device.

Note: If the key you enter in this field does not match the key configured on the target SNMP device, you will not get an error message about this! Please enter a string or leave the field empty.

Context Name

This setting is only visible if you select SNMP version v3 above. Enter a context name only if it is required by the configuration of the device. Context is a collection of management information accessible by an SNMP device. Please enter a string.

SNMP Port

Enter the port for the SNMP communication. We recommend that you use the default value.

SNMP Timeout (Sec.)

Enter a timeout in seconds for the request. If the reply takes longer than the value you enter here, the request is aborted and an error message triggered.

Scanning Interval

Scanning Interval

Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration.

When a Sensor Reports an Error

Define the number of scanning intervals that a sensor has time to report an error before the sensor will be set to a Down status. The sensor can try to reach a device several times, depending on the setup you can specify here, to help avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:

  • Set sensor to "down" immediately: The sensor will show an error immediately after the first failed request.
  • Set sensor to "warning" for 1 interval, then set to "down" (recommended): After the first failed request, the sensor will show a yellow warning status. If the following request also fails, the sensor will show an error.
  • Set sensor to "warning" for 2 intervals, then set to "down": Show an error status only after three continuously failed requests.
  • Set sensor to "warning" for 3 intervals, then set to "down": Show an error status only after four continuously failed requests.
  • Set sensor to "warning" for 4 intervals, then set to "down": Show an error status only after five continuously failed requests.
  • Set sensor to "warning" for 5 intervals, then set to "down": Show an error status only after six continuously failed requests.

Note: Sensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval until they show an error. It is not possible to set a WMI sensor "down" immediately, so the first option will not apply to these sensor types (all other options can apply).

Note: If a sensor has defined error limits for channels, this sensor will always be set to a Down status immediately, so no "wait" option will apply.

Note: If a channel uses lookup values, the sensor will always be set to a Down status immediately, so no "wait" options will apply.

Schedules, Dependencies, and Maintenance Window

Note: Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted. The corresponding settings from the parent objects will always be active. However, you can define additional settings here. They will be active at the same time as the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) throughout the week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.

Note: Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active at the same time.

Maintenance Window

Specify if you want to set-up a one-time maintenance window. During a "maintenance window" period, this object and all child objects will not be monitored. They will be in a paused state instead. Choose between:

  • Not set (monitor continuously): No maintenance window will be set and monitoring will always be active.
  • Set up a one-time maintenance window: Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for a currently running maintenance window.

Note: To terminate a current maintenance window before the defined end date, you can change the time in Maintenance End At field to a date in the past.

Maintenance Begins At

This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance End At

This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the end date and time of the maintenance window.

Dependency Type

Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:

  • Use parent: Pause the current sensor if the device, where it is created on, is in a Down status, or if the sensor is paused by another dependency.
  • Select object: Pause the current sensor if the device, where it is created on, is in an Down status, or if the sensor is paused by another dependency. Additionally, pause the current sensor if a specific other object in the device tree is in a Down status, or if it is paused by another dependency. Select below.
  • Master object for parent: Make this sensor the master object for its parent device. The sensor will influence the behavior of the device, where it is created on: If the sensor is in a Down status, the device will be paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor will be paused if the parent group of its parent device is in a Down status, or if it is paused by another dependency.

Note: Testing your dependencies is easy! Simply choose Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later all dependent objects should be paused. You can check all dependencies in your PRTG installation by selecting Devices | Dependencies from the main menu bar.

Dependency

This field is only visible if the Select object option is enabled above. Click on the reading-glasses and use the object selector to choose an object on which the current sensor will depend.

Delay (Seconds)

Define a time span. After the master object for this dependency comes back to an Up status, the beginning of the monitoring of the depending objects will be additionally delayed by the time span you define here. This can help to avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value in seconds. Note: This setting is not available if you choose this sensor to be the Master object for parent. In this case, please define delays in the parent Device Settings or in the superior Group Settings.

Access Rights

User Group Access

Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown: It contains all user groups from your setup. For each user group you can choose from the following access rights:

  • Inherited: Use the access rights settings of the parent object.
  • None: Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.
  • Read: Users in this group can see the object and review its monitoring results.
  • Write: Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.
  • Full: Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.

You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.

For more details on access rights, please see the section User Access Rights.

More

Knowledge Base: My SNMP sensors don't work. What can I do?

Knowledge Base: I get the error PE123 when using the SNMP Cisco ASA VPN Traffic sensor. What can I do?

Edit Sensor Channels

To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, please see the Sensor Channels Settings section.

Notifications

Click the Notifications tab to change notification triggers. For detailed information, please see the Sensor Notifications Settings section.

Others

For more general information about settings, please see the Object Settings section.

Sensor Settings Overview

For information about sensor settings, please see the following sections:

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