Chapter 4 Configuring the Appliance 45
Configuring the host database
The appliance host database stores the domain name server (DNS) entries of
servers that the appliance contacts to fulfill user requests. You configure the
appliance host database by setting options in the Host Database Management
section. The following table describes the options.
Option Description
Lookup timeout Specifies the DNS lookup timeout in seconds. You can
choose from the following:
❚ 5 seconds
❚ 10 seconds
❚ 15 seconds
❚ 20 seconds
❚ 30 seconds
Foreground
timeout
Specifies how long DNS entries can remain in the database
before they are flagged as stale. You can choose from the
following:
❚ 12 hours
❚ 24 hours
❚ 48 hours
For example, if this timeout is 24 hours, and a user requests
an entry that has been in the database for 24 hours or longer,
the appliance will refresh the entry before serving it.
You can set the background timeout (see next item) to refresh
entries in the background, before objects become stale.
Be careful not to set the foreground timeout too low. Doing so
might slow response time. Additionally, setting the timeout
value too high risks accumulation of incorrect information.
Setting the foreground timeout to greater than or equal to the
background timeout disables background refresh.
