# LE Using Chached DNS lookups during DV process

**URL:** <https://community.letsencrypt.org/t/le-using-chached-dns-lookups-during-dv-process/2591>\
**Category:** Issuance Tech\
**Created:** [October 31, 2015, 12:53pm UTC](https://community.letsencrypt.org/t/le-using-chached-dns-lookups-during-dv-process/2591 "2015-10-31T12:53:52Z")\
**Posts on this page:** 5\
**Page:** 2

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**Author:** ![felixf](https://avatars.discourse-cdn.com/v4/letter/f/fbc32d/32.png) [@felixf](https://community.letsencrypt.org/u/felixf)\
**Post date:** [March 5, 2021, 7:46am UTC](https://community.letsencrypt.org/t/le-using-chached-dns-lookups-during-dv-process/2591/21 "2021-03-05T07:46:53Z")

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> [@arek](#):
>
> that fails because letsencrypt claims there are no acme records in [abc.mydomain.com](http://abc.mydomain.com) zone while they are, freshly added

Have you **verified** that **all** nameservers for that zone deliver the TXT records before telling Let's Encrypt to verify the challenges?

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**Author:** ![arek](https://avatars.discourse-cdn.com/v4/letter/a/46a35a/32.png) [@arek](https://community.letsencrypt.org/u/arek)\
**Post date:** [March 5, 2021, 7:50am UTC](https://community.letsencrypt.org/t/le-using-chached-dns-lookups-during-dv-process/2591/22 "2021-03-05T07:50:19Z")

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> [@felixf](#):
>
> Have you **verified** that **all** nameservers for that zone deliver the TXT records before telling Let's Encrypt to verify the challenges?

Yes. Our tool here first checks if all our DNS have acme records propagated correctly and only then sends request to letsencrypt.

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**Author:** ![bruncsak](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/bruncsak/32/18414_2.png) [@bruncsak](https://community.letsencrypt.org/u/bruncsak)\
**Post date:** [March 5, 2021, 1:10pm UTC](https://community.letsencrypt.org/t/le-using-chached-dns-lookups-during-dv-process/2591/23 "2021-03-05T13:10:34Z")

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The ACME server (boulder) has 1 minute DNS cache, if my recollection is correct.

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**Author:** ![rmbolger](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/rmbolger/32/27474_2.png) [@rmbolger](https://community.letsencrypt.org/u/rmbolger)\
**Post date:** [March 5, 2021, 4:00pm UTC](https://community.letsencrypt.org/t/le-using-chached-dns-lookups-during-dv-process/2591/24 "2021-03-05T16:00:17Z")

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I believe it's 1 minute or the value of the TTL on the record, whichever is lower.

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**Author:** ![jsha](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/jsha/32/12_2.png) [@jsha](https://community.letsencrypt.org/u/jsha)\
**Post date:** [March 26, 2021, 6:50pm UTC](https://community.letsencrypt.org/t/le-using-chached-dns-lookups-during-dv-process/2591/25 "2021-03-26T18:50:58Z")

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