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How to use a CNAME for sharepoint DR? RRS feed

  • Question

  • Hi,

    I have SharePoint deployed in a stretched farm configuration between 2 data centres. (DC.) 

    There are 2 Kemp load balancers - one in the 1st DC & one on the 2nd DC.

    Production uses DC 1.

    DR is to DC 2.

    I am being asked to create DNS CNAME records that can be edited to direct clients from DC1 to DC 2.

    I've read a bit on this but am very confused - i think this should be easy but finding relevant info to explain this for SharePoint is starting to get very tedious.

    • Can anyone please direct me to clear simple easy to understand info on using cnames for SharePoint DR?



    Friday, June 21, 2019 1:10 PM

All replies

  • Just use an A record. The A record can be edited at any time.

    Trevor Seward

    Office Servers and Services MVP



    Author, Deploying SharePoint 2016

    This post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, its employees, or other MVPs.

    Friday, June 21, 2019 3:33 PM

  • Hi xyz2012, 

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    Monday, June 24, 2019 6:36 AM
  • Hi,

    My client wants to use a CNAME....how?

    (DNS A records make perfect sense to use - but the customer wants a CNAME)

    How to do this?

    Monday, June 24, 2019 10:03 AM
  • No sadly it does not - my client wants to use a cname...how?
    Monday, June 24, 2019 10:04 AM
  • A CNAME just points to an A record. The A record points to the load balancer IP.

    CNAME -> A record -> IP

    You can't skip the A record part of this.


    Trevor Seward

    Office Apps and Services MVP



    Author, Deploying SharePoint 2019

    Author, Deploying SharePoint 2016

    This post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, its employees, or other MVPs.

    Monday, June 24, 2019 7:25 PM
  • I'm not saying to skip the A record...I'm asking how to use a CNAME for DR...
    Tuesday, June 25, 2019 10:29 AM
  • You'd want to use the same URL for prod and DR to prevent end user confusion which means the same DNS record text. Again, needlessly complicating and/or misunderstanding the use of a CNAME. It doesn't apply in this case. You'll just update the A record with the new IP once a DR event has occurred. 

    Trevor Seward

    Office Apps and Services MVP



    Author, Deploying SharePoint 2019

    Author, Deploying SharePoint 2016

    This post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, its employees, or other MVPs.

    Tuesday, June 25, 2019 3:46 PM
  • Hi,

    I'm not entirely sure this is correct: "needlessly complicating and/or misunderstanding the use of a CNAME"

    Using a cname makes sense as in theory it means one dns edit (the A record) to affect 2 web apps...Where the 2 web apps use cnames so it might be like this:

    cname (web app) points to dns a record that via ip points to the kemp virtual service...

    You might be right though - i'd rather only use dns A records BUT this client is saying they want the DR switch being thrown using a cname not an "A record" - it's too early to know if this is complicating/misunderstanding things - the person who asked me to do this is very technical and very good at sharepoint - but he might have it wrong...


    • Edited by xyz2012 Tuesday, June 25, 2019 4:35 PM
    Tuesday, June 25, 2019 4:32 PM
  • SharePoint will respond on the URL it is configured to do so. CNAME defeats that purpose since the CNAME points to the A record (that SharePoint would respond to). The LB doesn't come into play, here.

    A record of SharePoint FQDN -> IP of Kemp -> SharePoint server(s)

    What is the point of putting a CNAME in front of that?


    Trevor Seward

    Office Apps and Services MVP



    Author, Deploying SharePoint 2019

    Author, Deploying SharePoint 2016

    This post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, its employees, or other MVPs.

    Tuesday, June 25, 2019 5:11 PM