Specifications

Chapter 3: Configuring the Barracuda Link Balancer 35
DNS Records
DNS Records Generated when Creating a Domain
When you create a domain on the Barracuda Link Balancer the following records are automatically
generated:
• Start of Authority (SOA) record - The SOA record defines the global parameters for the hosted
domain or zone. Only one SOA record is allowed per hosted domain or zone.
• Name Server (NS) record - NS records specify the authoritative name servers for this domain.
One NS record for each name server in the DNS Server Listen Links table is generated.
• Address (A) record - A records map a hostname to an IP address. Each host inside the domain
should be represented by an A record. One A record is created for each name server in the DNS
Server Listen Links table. An A record is also created for each matching domain name found in
1:1 NAT and Port Forwarding rules.
Additional DNS Records
Once a zone has been created, you can edit the above records or add NS, A and any of the following
records to a zone:
• Mail Exchanger (MX) record - MX records point to the email servers that are responsible for
handling email for a given domain. There should be an MX record for each email server,
including backup email servers if they exist. If an email server lies within the domain it requires
an A record for each name server. If the email server is outside the domain, specify the FQDN of
the server, ending with a dot. Example: mail.my-isp.net.
• Text (TXT) record - Text records allow text to be associated with a name. This can be used to
specify Sender Policy Framework (SPF) or DomainKeys records for the domain.
• Canonical Name (CNAME) record - A CNAME record provides a mapping between this alias
and the true, or canonical, hostname of the computer. It is commonly used to hide changes to the
internal DNS structure. External users can use an unchanging alias while the internal names are
updated. If the real server is outside the domain, specify the FQDN of the server, ending with a
dot. Example: server1.my-isp.net. If a domain name has a CNAME record associated with it,
then it can not have any other record types. Do not use CNAME defined hostnames in MX
records.
• Service (SRV) record - Service records are used to store the location of newer protocols, such as
SIP, LDAP, IMAP and HTTP.
• Pointer (PTR) record - PTR records point to a canonical name. The most common use is to
provide a way to associate a domain name with an IP address.
• Other (OTHER) record - Use an OTHER record to add a type of DNS record that is not
supported, such as NAPTR.
More information about these records and their attributes can be found in the online help.
Configuring Administrative Settings
This section describes the configuration tasks you can perform from the Web user interface. The
following topics are covered:
Controlling Access to the Web User Interface................................... 36
Changing the Default Password ........................................................ 36