SFW VPN Details Test

Virtual private network technology is based on the idea of tunneling. A Tunnel is nothing but a logical network connection in the internet cloud through which the send and receive data requests travel. When you initiate communication or send data over VPN network, the Tunneling protocol(s) used by the VPN network (like PPTP, L2TP, IPSec etc.) wraps up the data packets into another data packet and encrypts the package that is to be sent through the tunnel. At receiver’s end, the tunneling device/protocol deciphers the package and then strips the wrapped data packet to read and access the original message and reveal the source of packet and other classified information.

Using the Sonic firewall, administrators can configure multiple VPN tunnels based on the volume of data traffic handled by their network and the security/privacy requirements of the network. Access policies and QoS rules can be configured for VPN tunnels, and bandwidth management can be enabled on these configurations to prevent unauthorized access to the network and to optimize the usage of network resources. Improper firewall configurations can therefore result in a few VPN tunnels hogging the bandwidth resources and choking the network! To avoid this, administrators should periodically check the efficacy of the firewall configuration, spot holes in the settings, and plug the holes! This is where the SFW VPN Details test helps! This test auto discovers the VPN tunnels configured using the Sonic firewall and closely monitors the amount of data and packets sent and received via every tunnel. In the process, the test accurately points to that tunnel that is handling an abnormally high volume of traffic and is hence hogging the bandwidth resources available to the network! This way, the test enables administrators to understand whether/not their firewall configurations are effective, and if not, initiate measures to fine-tune them.

Target of the test : A SonicWall Firewall device

Agent deploying the test : An external agent

Outputs of the test : One set of results for each VPN tunnel that is to be monitored.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The IP address of the Sonic firewall for which this test is to be configured.

Port

Refers to the port at which the Sonic firewall listens to.

SNMPPort

The port at which the monitored target exposes its SNMP MIB; The default value is 161.

SNMPVersion

By default, the eG agent supports SNMP version 1. Accordingly, the default selection in the SNMPversion list is v1. However, if a different SNMP framework is in use in your environment, say SNMP v2 or v3, then select the corresponding option from this list.

SNMPCommunity

The SNMP community name that the test uses to communicate with the firewall. This parameter is specific to SNMP v1 and v2 only. Therefore, if the SNMPVersion chosen is v3, then this parameter will not appear.

UserName

This parameter appears only when v3 is selected as the SNMPVersion. SNMP version 3 (SNMPv3) is an extensible SNMP Framework which supplements the SNMPv2 Framework, by additionally supporting message security, access control, and remote SNMP configuration capabilities. To extract performance statistics from the MIB using the highly secure SNMP v3 protocol, the eG agent has to be configured with the required access privileges – in other words, the eG agent should connect to the MIB using the credentials of a user with access permissions to be MIB. Therefore, specify the name of such a user against this parameter. 

Context

This parameter appears only when v3 is selected as the SNMPVersion. An SNMP context is a collection of management information accessible by an SNMP entity. An item of management information may exist in more than one context and an SNMP entity potentially has access to many contexts. A context is identified by the SNMPEngineID value of the entity hosting the management information (also called a contextEngineID) and a context name that identifies the specific context (also called a contextName). If the Username provided is associated with a context name, then the eG agent will be able to poll the MIB and collect metrics only if it is configured with the context name as well. In such cases therefore, specify the context name of the Username in the Context text box.  By default, this parameter is set to none.

AuthPass

Specify the password that corresponds to the above-mentioned Username. This parameter once again appears only if the SNMPversion selected is v3.

Confirm Password

Confirm the AuthPass by retyping it here.

AuthType

This parameter too appears only if v3 is selected as the SNMPversion. From the Authtype list box, choose the authentication algorithm using which SNMP v3 converts the specified username and password into a 32-bit format to ensure security of SNMP transactions. You can choose between the following options:

  • MD5 – Message Digest Algorithm
  • SHA – Secure Hash Algorithm

EncryptFlag

This flag appears only when v3 is selected as the SNMPversion. By default, the eG agent does not encrypt SNMP requests. Accordingly, the this flag is set to No by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the Yes option. 

EncryptType

If this EncryptFlag is set to Yes, then you will have to mention the encryption type by selecting an option from the EncryptType list. SNMP v3 supports the following encryption types:

  • DES – Data Encryption Standard
  • AES – Advanced Encryption Standard

EncryptPassword

Specify the encryption password here.

Confirm Password

Confirm the encryption password by retyping it here.

Timeout

Specify the duration (in seconds) within which the SNMP query executed by this test should time out in this text box. The default is 10 seconds.

Data Over TCP

By default, in an IT environment, all data transmission occurs over UDP. Some environments however, may be specifically configured to offload a fraction of the data traffic – for instance, certain types of data traffic or traffic pertaining to specific components – to other protocols like TCP, so as to prevent UDP overloads. In such environments, you can instruct the eG agent to conduct the SNMP data traffic related to the monitored target over TCP (and not UDP). For this, set this flag to Yes. By default, this flag is set to No.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Fragmented received packets

Indicates the number of fragmented packets that are received through this VPN tunnel.

Number

 

Fragmented transmitted packets

Indicates the number of fragmented packets that are transmitted through this VPN tunnel.

Number

Comparing the value of this measure across the VPN tunnels helps you in identifying the VPN tunnel that is transmitting the highest number of fragmented packets.

A very high value for this measure could imply that the MTU (Maximum Transmission Unit) set for the WAN interface is very low, causing many packets to be unnecessarily fragmented. To reduce the load on the network link, you may want to consider resetting the MTU.

Encrypted data

Indicates the total amount of data that was encrypted by this VPN tunnel.

KB

Comparing the values of these measures across the VPN tunnels helps you in identifying the VPN tunnel that has encrypted/decrypted the maximum amount of data – i.e., the VPN tunnel that has consumed the maximum bandwidth over the network link.

If the gap between the top and the least bandwidth consumers is very wide, it could indicate that one/more tunnels are hogging the bandwidth resources. You may then have to consider enabling bandwidth management on these VPN tunnels, reconfigure access policies, or fine-tune QoS settings, so as to minimize bandwidth usage.

Decrypted data

Indicates the total amount of data that was decrypted by this VPN tunnel.

KB

Encrypted packets

Indicates the number of packets that were encrypted on this tunnel.

Number

Comparing the values of these measures across the VPN tunnels helps you in identifying the VPN tunnel that has encrypted/decrypted the maximum number of packets – i.e., the VPN tunnel that has consumed the maximum bandwidth over the network link.

If the gap between the top and the least bandwidth consumers is very wide, it could indicate that one/more tunnels are hogging the bandwidth resources. You may then have to consider enabling bandwidth management on these VPN tunnels, reconfigure access policies, or fine-tune QoS settings, so as to minimize bandwidth usage.

Decrypted packets

Indicates the number of packets that were decrypted by this tunnel.

Number