Specifications

Chapter 3: Configuring the Barracuda Link Balancer 21
Creating IP Aliases
You can create virtual interfaces or IP aliases by associating an IP address or subnet with a WAN,
LAN or VLAN. Each IP address and netmask can only be associated with one WAN, LAN or VLAN.
Virtual interfaces are used:
• to associate an IP address range with a VLAN
• to associate an externally accessible IP address that is on a different subnet than any WAN link
with a WAN link.
Create IP aliases using the
Advanced > Advanced IP Config page.
Configuring DNS Servers
Use the Basic > Links page to set the primary and secondary DNS servers for each WAN link. Your
ISP should provide you with these settings.
Configuring Per Interface Health Checks
Use the Basic > Links page to configure health checks for each link. Multiple methods are supported.
You can enter more than one test target (e.g. resolve the DNS domain names of multiple Web sites)
to be sure that the link is actually down. Link failure is shown on this page and on the
Basic > Status
page. Also, if a link fails an SNMP trap will be generated, an email will be sent, and an event will be
logged.
Configuring the DHCP Server
The Barracuda Link Balancer can act as a DHCP server. Use the Services > DHCP Server page to
enable the DHCP server and to configure it.
Configuring the Firewall
The Barracuda Link Balancer can act as a firewall, inspecting network traffic as it arrives and
allowing or denying passage based on a set of rules. These rules include inbound, outbound, 1:1 NAT
and port forwarding rules. Some of this functionality is available even if the firewall is disabled.
This section covers the following topics:
Firewall Functionality ....................................................................... 22
Order of Execution of Firewall Rules................................................ 22
Inbound Firewall Rules ..................................................................... 22
Inbound 1:1 NAT Rules ..................................................................... 22
Port Forwarding Rules ...................................................................... 23
Outbound Firewall Rules................................................................... 23
Firewall Logging ............................................................................... 23