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Barracuda Link Balancer

How do I configure My Barracuda Link Balancer to Route traffic to and from my Barracuda Phone System?

  • Type: Knowledgebase
  • Date changed: 8 months ago

Solution #00005815

 

Scope:

This solution applies to all Barracuda Link Balancers passing traffic for any Barracuda Phone System.


Answer:

The network configuration settings on the Barracuda Link Balancer are designed to enable balancing links between multiple Service Providers and/or circuits. Voice over IP, however, is a UDP-based session, requiring a single point of termination for it's traffic by the nature of the technology itself. The Barracuda Link balancer is designed to allow this, with minor additional configuration necessary. This solution provides the steps necessary to configure the Barracuda Link Balancer to properly route the traffic in this way. This solution assumes that the Link Balancer is already configured for general use, and that the Barracuda Phone System is already physically installed on your local network with the Link Balancer set as the Default Gateway for the LAN adapter.

 

There are four basic steps to setting up the Barracuda Link Balancer to properly pass VoIP traffic for the Barracuda Phone System.

We will cover each of these in order:


  1. Determining which WAN Link to use for the Barracuda Phone System.
  2. Configuring Services for the Barracuda Phone System.
  3. Configuring the Outbound Route for your Barracuda Phone System.
  4. Configuring the Firewall to allow the services necessary for the Barracuda Phone System.

These steps will take only a few minutes to complete, and will allow the Barracuda Phone System to work properly with remote Providers, Sites, and Devices.



Step 1 - Determining which WAN Link to use, and configuring services for, the Barracuda Phone System:

From the Link Balancer, Navigate to Basic > Links and Determine which WAN Link you wish to use for the Barracuda Phone System. Please make sure to note the Name chosen for the interface, and the IP address which it is using. You will be using these settings in Steps 3 and 4. Please remember that this IP address will need to be used for remote device access and web access, as well as for any providers that require your WAN IP address.


Step 2 - Configuring Services for the Barracuda Phone System:

The Barracuda Link Balancer uses a robust set of application rules to allow or deny traffic for your network. Adding the proper service definitions for the Cudatel Communications Server is the easiest way to ensure that it is easy to manage in the future. Some services, specifically SMTP (Send E-Mail), Web, and NTP, are pre-defined. we will need to add a few more services in order to make sure the Cudatel works as desired.
  1. Navigate to Policy > Applications and scroll to the section labelled Custom Applications.
  2. Enter the following information in the appropriate fields of the New Application line:
    • Name - BPS SIP 
    • Protocol - TCP 
    • Port/Range - 5060-5070
  3. Click Add to finish configuring settings for this service.
  4. Repeat Step 2, entering the following information in the appropriate fields of the New Application line:
    • Name - BPS RTP
    • Protocol - UDP 
    • Port/Range - 16384-32768
  5. Click Add to finish configuring settings for this service.
  6. Click Save at the top of the Custom Applications Section to finish adding Services.
If you are routing mail to a SmartHost or mail server on ports other than 25, configuring FTP or SMB backups to a remote site, or using the alternative management port for the Barracuda Phone System, then you will need to add these services, as well. Please contact Support if you need assistance.

Step 3 - Configuring the Outbound Route for your Barracuda Phone System:

In order to properly communicate with external phones and servers/services, the Barracuda Phone System must send outbound traffic out the same link from which it is going to receive it. completing these steps will ensure that the Barracuda Phone System follows this behavior:

  1. Navigate to Policy > Outbound Routing.
  2. Add the Following Entry In the section labeled IP/Application Routing:
    • Rule Name -  BPS
    • Source IP Address - BPS LAN IP
    • Source Netmask - 255.255.255.255
    • Application - Select * from the Drop-down
    • Destination IP Address - 0.0.0.0
    • Destination Netmask - 0.0.0.0
    • Link Balance  - Select No
    • Primary Link - Select the WAN Link chosen in step 1
    • Backup Link - Select None ***This is VERY Important***
    • NAT - Check
  3. Click Add to finish editing this entry.
  4. Click Save to finish with the Section IP/Application routing
  5. Add the Following Entry the Section labeled Outbound Source NAT:
    • Rule Name - BPS NAT
    • Source IP Address - Enter the LAN IP Address of the Barracuda Phone System.
    • Source Netmask - 255.255.255.255
    • Application - Select * from the Drop-down
    • Link - Select the WAN Link chosen in step 1
    • Masquerade IP Address/Range - Enter the IP chosen in Step 1
  6. Click Add to finish editing this entry.
  7. Click Save to finish with the section Outbound source NAT.

Step 4 - Configuring the Inbound Route for your Barracuda Phone System:
In order for external devices and services to properly communicate with the Barracuda Phone System, you must set up the inbound firewall rule and assign the services to the IP address of the BPS. Completing these steps will ensure that the Barracuda Phone System follows this behavior:

  1. Navigate to Firewall > Inbound
  2. Click Add New Firewall Rule
  3. Add the Following Entry In the new window which appears:
    • Rule Name - BPS SIP
    • Action - Select Allow
    • Link - Select the WAN Link chosen in step 1
    • Protocol - TCP
    • Source IP Address - 0.0.0.0
    • Subnet Mask - 0.0.0.0
    • Destination IP Address - BPS LAN IP Address
    • Subnet Mask - 255.255.255.255
    • Application - Select the Application BPS SIP
    • Description - (Optional) Enter a description as a reminder that this is used for the Barracuda Phone System.
  4. Click Add Rule to complete
  5. Repeat this step for the following applications, replacing the name and description to match the service added:
    • BPS RTP
    • SMTP (Send E-mail)
    • Web
    • NTP

Your Link Balancer should now be configured to properly pass traffic to and from the Barracuda Phone System, and the link will still be used for link balancing the other WAN links..


    Important Note for Firmware version 2.4.x and Later
    Link Balancer firmware versions 2.4 and later include an option to disable the SIP ALG on the expert variables page. This box should be unchecked for best behavior. Please call support for assistance if you do not have access to this page.


    Link to this page:

    https://campus.barracuda.com/solution/50160000000IdrXAAS