Where dns store its cached entry

Hello all,

I'm curious where dns/bind stores its cached domain
entry. Is it on memory or a file on the disk?

If it's in memory, what will happen to the dns cache when we restart the computer?

I'm sorry for asking stupid question.

Thanks,
Stand

hstanditAsked:
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wesly_chenCommented:
cache in memory.

> what will happen to the dns cache when we restart the computer
The cache will be wiped out cleanly after reboot or restart the named.

Wesly
0

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hstanditAuthor Commented:
Hello,

Thank you for your answer. So this case, if my name server is polluted or it caches www.example.org as 192.168.1.1 while www.example.org has just been updated to 192.168.2.2, does restart named/computer solve the problem?

Thanks again,
Stand
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chris_calabreseCommented:
Yes.

It will also throw out the cache entry for ww.example.org once the time-to-live for the entry is reached. Therefore, when making a change to a publicly-visible host, it's usually done by first setting the TTL to something short (like 5 minutes), waiting for the original TTL to expire (usually something like 24 hours), making the change, and then setting the TTL back to normal.
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hstanditAuthor Commented:
Hi Chris,

I know the concept of TTL. I was asking if restarting named would make my named start learning ip address of www.example.org again.

Thank you,

Stand
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wesly_chenCommented:
> restarting named would make my named start learning ip address of www.example.org again.
Yes.

Wesly
0
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