Chapter 20 DNS
The following table describes the labels in this screen.
Table 117 ADVANCED > DNS > Cache
LABEL | DESCRIPTION |
DNS Cache Setup |
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Cache Positive DNS | Select the check box to record the positive DNS resolutions in the cache. |
Resolutions | 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. |
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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. |
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Cache Negative | Caching negative DNS resolutions helps speed up the ZyWALL’s processing of |
DNS Resolutions | commonly queried domain names (for which DNS resolution has failed) and |
| reduces the amount of traffic that the ZyWALL sends out to the WAN. |
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Negative Cache | Type the time (60 to 3600 seconds) that the ZyWALL is to allow a negative |
Period | resolution entry to remain in the DNS cache before discarding it. |
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Apply | Click Apply to save your changes back to the ZyWALL. |
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Reset | Click Reset to begin configuring this screen afresh. |
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DNS Cache Entry |
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Flush | 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. |
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Refresh | Click this button to reload the cache. |
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# | This is the index number of a record. |
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Cache Type | This displays whether the response for the DNS request is positive or negative. |
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Domain Name | This is the domain name of a host. |
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IP Address | This is the (resolved) IP address of a host. This field displays 0.0.0.0 for |
| negative DNS resolution entries. |
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Remaining Time | This is the number of seconds left before the DNS resolution entry is discarded |
(sec) | from the cache. |
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Modify | Click the delete icon to remove the DNS resolution entry from the cache. |
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20.9 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, DMZ or WLAN DHCP clients.
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ZyWALL 2 Plus User’s Guide |
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