Avoiding an outage.
RECORD EVERYTHING FIRST
Every existing record, exactly, including ones you do not recognise
ESTABLISH
Where DNS is actually managed Where the nameservers currently point Current TTL values
PREPARE
Lower TTLs well in advance of the change Create all records at the new provider before switching, if changing nameservers
CHECK SPECIFICALLY
MX records, for mail TXT records for mail authentication Verification records for third-party services Any subdomain records
MAKE THE CHANGE
One thing at a time where possible Outside busy periods
VERIFY
The name resolves as intended, from more than one resolver The site loads Mail sends and receives Certificates are valid
AFTERWARDS
Raise TTLs once stable Keep the old records until certain Update your documentation
WHAT NOT TO DO
Change nameservers without recreating records first.
