Configuring Dns Dhcp; Table 102 Dns Cache - ZyXEL Communications ZyWALL 2Plus User Manual

ZyWALL 2 Plus User's Guide
The following table describes the labels in this screen.

Table 102 DNS Cache

LABEL
DNS Cache Setup
Cache Positive DNS
Resolutions
Maximum TTL
Cache Negative
DNS Resolutions
Negative Cache
Period
Apply
Reset
DNS Cache Entry
Flush
Refresh
#
Cache Type
Domain Name
IP Address
Remaining Time
(sec)
Modify

17.9 Configuring DNS DHCP

Click ADVANCED > DNS > DHCP to open the DNS DHCP screen shown next. Use this
screen to configure the DNS server information that the ZyWALL sends to its LAN DHCP
clients.
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DESCRIPTION
Select the check box to record the positive DNS resolutions in the cache.
Caching positive DNS resolutions helps speed up the ZyWALL's processing of
commonly queried domain names and reduces the amount of traffic that the
ZyWALL sends out to the WAN.
Type the maximum time to live (TTL) (60 to 3600 seconds). This sets how long
the ZyWALL is to allow a positive resolution entry to remain in the DNS cache
before discarding it.
Caching negative DNS resolutions helps speed up the ZyWALL's processing of
commonly queried domain names (for which DNS resolution has failed) and
reduces the amount of traffic that the ZyWALL sends out to the WAN.
Type the time (60 to 3600 seconds) that the ZyWALL is to allow a negative
resolution entry to remain in the DNS cache before discarding it.
Click Apply to save your changes back to the ZyWALL.
Click Reset to begin configuring this screen afresh.
Click this button to clear the cache manually. After you flush the cache, the
ZyWALL must query the DNS servers again for any domain names that had
been previously resolved.
Click this button to reload the cache.
This is the index number of a record.
This displays whether the response for the DNS request is positive or negative.
This is the domain name of a host.
This is the (resolved) IP address of a host. This field displays 0.0.0.0 for
negative DNS resolution entries.
This is the number of seconds left before the DNS resolution entry is discarded
from the cache.
Click the delete icon to remove the DNS resolution entry from the cache.
Chapter 17 DNS