DNS

DNS is critical for all types of web applications because it allows us to use domain names—for instance www.citrix.com—instead of remembering IP addresses. It also helps SSL-based web applications with certificates to work since the trust underneath is built upon the hostname attribute or FQDN. DNS is also crucial for GSLB because it is mainly a DNS-based load-balancing feature.

NetScaler can operate as its own authoritative DNS server or use another DNS server as source and NetScaler can also serve as a proxy between authoritative DNS servers and clients.

Now by default if we add an external DNS server, the DNS communication between the NetScaler and the DNS server is sourced from the SNIP address, which is closest to the source. This means that if we have multiple SNIP addresses it will choose the closest.

To add an external DNS server we can use the following command:

Add nameserver ip-address –type UDP

Note

There are other options under parameter –type: UDP, TCP, or UDP_TCP. Regular DNS...