Comtech EF Data CDM-840 - Manual (Page 124)

CDM-840 Remote Router Revision 2
Ethernet-based Remote Product Management MN-CDM840
6–56
6.4.4.5.3.4 Configuration | Network | DNS
Use this page to manage DNS (Domain Name System) caching. DNS caching speeds up Internet
access by eliminating subsequent queries over the satellite link.
Figure 6-28. Configuration | Network | DNS Page
Note the following:
• When the CDM-840 receives a DNS query at one of its Ethernet Ports, a DNS cache look
up is performed in the local DNS cache. If the entry is found, a DNS response message is
immediately returned to the requesting entity with a time-to-live value of 10 seconds. If
no match is found, the request packet is forwarded to the Hub.
• When a DNS response packet is received from Hub, a check is made to see if the entry
already exists in the cache. If it exists, the time-to-live for the entry is reset to 900
seconds (15 minutes). If it’s a new entry it is added to the cache with time-to-live set to
900 seconds (15 minutes).
• The local DNS cache is periodically cleaned by removing expired entries
DNS Caching
Use the drop-down list to set DNS as Enabled or Disabled. Click [Submit] to save.
DNS Cache Flush
Click [Flush] to clear the DNS Cache of all data.