# Using CNAME record for DNS validation

**URL:** <https://community.letsencrypt.org/t/using-cname-record-for-dns-validation/121572>\
**Category:** Help\
**Created:** [May 4, 2020, 3:46am UTC](https://community.letsencrypt.org/t/using-cname-record-for-dns-validation/121572 "2020-05-04T03:46:33Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jaiswalok](https://avatars.discourse-cdn.com/v4/letter/j/ce73a5/32.png) [@jaiswalok](https://community.letsencrypt.org/u/jaiswalok)\
**Post date:** [May 4, 2020, 3:46am UTC](https://community.letsencrypt.org/t/using-cname-record-for-dns-validation/121572/1 "2020-05-04T03:46:33Z")

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Hi Folks,

need another help based on the discussion on the below thread.

> [@Cert Signing for Common SAN Entry on Two servers](https://community.letsencrypt.org/t/cert-signing-for-common-san-entry-on-two-servers/121340):
>
> H…

I read further on the DNS validation using CNAME at

> **[Onboarding Your Customers with Let's Encrypt and ACME - Let's Encrypt](https://letsencrypt.org/2019/10/09/onboarding-your-customers-with-lets-encrypt-and-acme.html)**
>
> If you work at a hosting provider or CDN, ACME’s DNS-01 validation method can make it a lot easier to onboard new customers who have an existing HTTPS website at another provider. Before your new customer points their domain name at your servers, you...

I believe with the DNS validation it will allow me to use the **same SAN Entry** (**[collab.example.com](http://collab.example.com)**) on both the servers (running in an Active-Active cluster mode) certificate.

I am looking to understand the format for creating this CNAME entries. Not a DNS guy much so any help will be appreciated. For e.g. if i need to create a CNAME entry for host **[collab.example.com](http://collab.example.com)**.

Regards,  
Alok

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**Author:** ![Osiris](https://avatars.discourse-cdn.com/v4/letter/o/839c29/32.png) [@Osiris](https://community.letsencrypt.org/u/Osiris)\
**Post date:** [May 4, 2020, 5:25am UTC](https://community.letsencrypt.org/t/using-cname-record-for-dns-validation/121572/2 "2020-05-04T05:25:07Z")

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The CNAME part of that article is mainly for hosting providers which provide certificates for their customers with hostnames outside of the control of the hosting provider. Note the difference between `example.com` and `example.net` in the article: the former is of the customer, the latter is of the hosting provider.

In your case you probably can use the `dns-01` challenge _without_ a CNAME record in the sense it doesn’t conform to the example of the article.

That said, if you’re running multiple servers which would use _the same_ certificate, it’s best to designate _one_ of your servers for the whole ACME/getting a certificate process and redistribute that certificate to all other servers.

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**Author:** ![system](https://global.discourse-cdn.com/letsencrypt/original/3X/c/a/ca6c06ea1ea201324bba7048c6841ce60236468d.png) [@system](https://community.letsencrypt.org/u/system)\
**Post date:** [June 3, 2020, 5:25am UTC](https://community.letsencrypt.org/t/using-cname-record-for-dns-validation/121572/3 "2020-06-03T05:25:13Z")

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