TTL set to 20 years - How do I fix?

Kevin Darcy kcd at
Thu Oct 18 23:46:47 UTC 2001

Jorey Bump wrote:

> Just kidding. I didn't really set the TTL that high. But I'm asking because
> a site that links to ours just changed hosts, and it's taking forever for
> us to get pages from the new server.
> It occurred to me that an administrator could make a mistake, and set the
> TTL too high, which should cause big trouble. What is the hard upper limit
> that bind will allow, and how would one correct this if it were cached
> 'round the world?

According to the _DNS_and_BIND_ book, the default maximum TTL is a week, but
this is configurable in BIND 9 (the "max-cache-ttl" option).

There's really no way to "correct" a huge TTL once the relevant records are in
the wild. That's why it's important to set TTL values carefully, preferably
through some sort of automated process where there is far less possibility of
an extra/missed character, or a character transposition.

- Kevin

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