8 configure dns cache, Figure 171 cache, Table 118 cache – ZyXEL Communications ZyXEL ZyWALL 35 User Manual

Page 346

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ZyWALL 35 User’s Guide

344

Chapter 20 DNS

20.8 Configure DNS Cache

To configure your ZyWALL’s DNS caching, click DNS, then the Cache tab. The screen
appears as shown.

Figure 171 Cache

The following table describes the labels in this screen.

Table 118 Cache

LABEL

DESCRIPTION

DNS Cache Setup

Cache Positive DNS

Resolutions

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.

Maximum TTL

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.

Cache Negative

DNS Resolutions

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.

Negative Cache

Period

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.

Apply

Click Apply to save your changes back to the ZyWALL.

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