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Speed up DNS lookups
Authored by: gmachen on Jun 06, '07 05:17:19PM

The OpenDNS website's instructions say to replace one's current two DNS addresses with their two OpenDNS addresses in the Mac OS X Network prefPane, then restart.

1) Is there any reason I can't have four addresses in there, first the two OpenDNS ones, then my two local ISP's?

2) Aren't one's DNS queries carried out in order of appearance of the DNS addresses as entered in one's Network prefPane; if one times-out then the next one is tried?

3) Does one really have to restart for them to take effect? I thought just clicking the Apply button did it on-the-fly. Are there caches or something involved that necessitate a restart?



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Speed up DNS lookups
Authored by: tuscantwelve on Jun 06, '07 07:19:43PM
1) Is there any reason I can't have four addresses in there, first the two OpenDNS ones, then my two local ISP's?

2) Aren't one's DNS queries carried out in order of appearance of the DNS addresses as entered in one's Network prefPane; if one times-out then the next one is tried?

3) Does one really have to restart for them to take effect? I thought just clicking the Apply button did it on-the-fly. Are there caches or something involved that necessitate a restart?
To answer your questions in detail:

1) No, you may add as many DNS server addresses as you like.

2) Sort of. First, lookupd's cache is consulted, then DNS, (then NetInfo, and finally, NIS/flatfiles, if enabled through Directory Access).

3) There are two ways to flush the cache of lookupd - as an administrator, the following commands will accomplish what you want:
 $ lookupd -flushcache
Or, if you prefer,
 $ sudo killall -HUP lookupd 
HTH.

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Speed up DNS lookups
Authored by: lolopb on Jun 07, '07 12:32:44PM
Hi,
2) Sort of. First, lookupd's cache is consulted, then DNS, (then NetInfo, and finally, NIS/flatfiles, if enabled through Directory Access).
Well, for hosts lookup, the configuration of lookupd is a little bit different and, so, the order of the agents used is different. The good order in this case is : Cache, Flat-Files (such as /etc/hosts), DNS, NetInfo and DirectoryService which can look in many places according to what's configured using /Applications/Utilities/Directory Access.app (LDAP, Active Directory, NIS and Flat Files...). To look at the configuration :
 lookupd -configuration 


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