where is the dns cache?

[常有慈悲心]

i want to know when use dns as name resolution.
if there is a dns cache on the client?
if there is ,is it a special process or a file to manage it?
if there isn't,
is there a cache on the server?

[Uday_S_Ankolekar · Accepted solution]

DNS cache on primary server is in /etc/named.data directory. It is in same place on secondary server too.

you need to configure /etc/nsswitch.conf file to look in to DNS on all the clients.
The hosts entry in nsswitch.conf file looks like this.
hosts: files [TRYAGAIN=continue NOTFOUND=continue] dns [NOTFOUND=continue]

-USA..

[harry d brown jr]

if there is a dns cache on the client?
---> Usually, but it depends on their configuration and OS

if there is ,is it a special process or a file to manage it?
---> Again it depends upon their configuration and OS - BUT NOT USUALLY

if there isn't, is there a cache on the server?
---> It depends upon which server, and in most cases it's in MEMORY, not in a file.


live free or die
harry d brown jr

[Geoff Wild]

On a DNS server - yes there is a cache - and it uses memory. No special file.

Client resolvers also have a cache - again no special file.

It stays in memory until the Time To Live expires - or you run out of memory.


Rgds...Geoff

[Dave Hutton]

If you are trying to troubleshoot a problem, and your client is Windows (XP or newer? I'm not sure) you can try from a dos command:
C:\ipconfig /flushdns

Which will clear your dns for your PC.

[Doug Kratky]

There are a couple of answers here implying that HP-UX does client-side DNS caching. Is that really true? Can you point to documentation or commands that would show that?

My understanding is that HP-UX does not do client-side DNS caching and that if caching is desired, then a caching-only name server had to be run on the client. Is that not necessary?