Network Troubleshooting / IT Support Guides
Understand DNS TTL during a service migration
After changing a DNS record, clients may continue to receive an older answer until caches expire. Inspect the returned TTL before repeatedly changing the record.
Environment and inputs: Mixed platforms · each example identifies its shell or required tool
Try the diagnostic command
Use the stated shell and platform. Replace sample domains, addresses, services and paths with values from the system you are authorized to support.
Resolve-DnsName example.com -Type A | Select-Object Name, IPAddress, TTLHow to read the result
Windows PowerShell displays address records and remaining TTL values supplied through the resolver. A cached reply may have a lower TTL than the authoritative record originally published.
What to do next
Compare the intended authoritative value with answers from the approved resolver. Plan migration overlap and allow existing cached records to age out rather than assuming every client switches instantly.
Before you make a change
Flushing one workstation cannot clear every upstream cache or application connection. Do not promise a universal cutover time from one TTL observation.