Is DNS flush needed on the clients when DNS alias is updated?

Question

We have a DNS alias set up for an SQL database server.

We will be upgrading the SQL server to a new machine, and the machine name will be different. DNS alias will be updated with the new name on the Domain Controller.

Question: Do I need to do ipconfig /flushdns on each machine that uses the alias for them to pick up the change or will it be resolved automatically.

That alias is used in many connection strings on many machines.

Thank you.

Why don't you just drop the TTL before the switch? – ceejayoz May 08 '13 at 16:30 — ceejayoz, May 08 '13 at 16:30

score 1 · Accepted Answer · answered May 08 '13 at 16:41

1

Assuming the DNS clients have the record in their DNS cache and you want them to resolve the new record immediately, then yes you would run ipconfig/flushdns on each client.

Two better alternatives to doing this are:

Make the change after hours.
Set the TTL to a low value (5 minutes) then wait for the TTL period after you make the change before running the application on the clients that need to resolve this DNS record.

answered May 08 '13 at 16:41

joeqwerty

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Glad to help... – joeqwerty May 08 '13 at 17:53

Is DNS flush needed on the clients when DNS alias is updated?

1 Answers1