Specifications

34 Barracuda Link Balancer Administrator’s Guide
my IN NS ns1
my IN NS ns2
ns1 IN A 216.101.241.181
ns2 IN A 192.0.2.2
Then you can create the my.example.com. domain on the Barracuda Link Balancer.
Step 6 - Test
From a host on the Internet, run nslookup on your domain name(s). The returned IP addresses should
be the IP addresses of your WAN listen links.
Depending on the change, it may take some time for your changes to be noted throughout the Internet,
depending on how long the various resolvers cache DNS responses. For example, it may take a day
before a new domain name is accessible via the Internet. If a domain name was previously registered
and the DNS record is modified, any server on the Internet that has the previous information will not
get the update until the TTL of the original record has passed.
If You Add a WAN Link After the Domains are Created
If, after creating your domains, you add a new WAN link, complete these steps to use the new link
for DNS queries (static links only) and inbound link balancing:
1. Go to the
Services > Authoritative DNS page.
2. If this is a static link and you want it to be used to respond to DNS queries:
• Identify the new link as a DNS Server Listen Link and assign it a Name Server label.
• For each domain that is already defined, add a new NS record and a new A record to each
domain for the new link.
3. Edit the A records for your servers to enable inbound traffic to be received on the new link for
the corresponding internal servers. Specifically, when you edit the A record, on the
DNS Record
page you can select the new WAN link from the Links list and add it to the A record.
Zones and Domains
A domain name server stores information about part of the domain name space called a zone. All
names in a given zone share the same domain suffix. For example, if barracuda.com is the domain
suffix, mail.barracuda.com and eng.barracuda.com are possible sub-domains. These may be all
served by one domain name server or some of the sub-domains may be delegated to other domain
name servers. Every domain or sub-domain is in exactly one zone.
Rather than make a distinction between a zone and a domain, the user interface of the Barracuda Link
Balancer simply asks you to create a domain.