User`s guide

Configure the following settings:

Web Security: Select .Proxy Forwarding

Proxy : Enter the IP address of the forward proxy.Forwarding

Port: Enter the port of the forward proxy. Default values are or .3128 8080

For example, if you are configuring a forward proxy for the setup in the figure above:

Click .Save Changes

How to Configure Authoritative DNS

The Barracuda Firewall can act as an authoritative DNS server, returning definitive

answers to DNS queries about domain names installed in its configuration. With DNS,

you can use the the same namespace internally and externally. You can direct external

clients to use one IP address, and internal clients to use an internal path to the same

hostname. This feature is also called Split DNS.

In this article:

Split DNS

Configuring Authoritative DNS

How Authoritative DNS Works

DNS Zone Transfer Blocking

Add a WAN Interface After the Domains are Created

Zones and Domains

DNS Records

How to Configure an Authoritative

DNS Host

Split DNS

The Barracuda Firewall supports a split DNS infrastructure. If the same hostname is used for a resource that is both internally and externally

accessible, internal network clients receive the internal IP address and external clients receive the external IP address when they ask for the

address of that hostname. Specifically, the A record for the hostname includes two views: one with the internal IP address and one with the

external IP address. Clients only see the address that they should use. For more details on how to configure split DNS, see "Step 3: Set up DNS

for Internal Clients" in .How to Configure an Authoritative DNS Host

If local clients use external IP addresses to access internal servers, the Barracuda Firewall translates the address and forwards those requests to

internal servers.

Configuring Authoritative DNS

For an overview of the steps required to make the Barracuda Firewall an authoritative DNS host, see How to Configure an Authoritative DNS Host

How Authoritative DNS Works

By configuring the Barracuda Firewall as the authoritative DNS server for the domains that are behind it, you increase the availability of your

hosted servers. When asked for the IP address of a hostname, the Barracuda Firewall returns a DNS A record that contains the IP address of one

of your WAN interfaces.