Ruling it out.
SYMPTOMS THAT LOOK LIKE DNS AND ARE NOT
- The site loads but shows an error: DNS worked; the application failed
- A certificate warning: DNS worked; the certificate is the issue
- Only you cannot reach it: a firewall block, not DNS
- The site loads slowly: DNS resolution is a fraction of a second
HOW TO RULE DNS OUT
Look up the domain. Does it return the correct address?
If yes, DNS is working and the problem is elsewhere.
That single check takes thirty seconds and eliminates a whole category.
WHAT DNS PROBLEMS ACTUALLY LOOK LIKE
The domain does not resolve at all It resolves to the wrong address Mail is not delivered because MX records are missing A subdomain does not resolve
WHAT THEY DO NOT LOOK LIKE
Errors from the server, which means the request arrived Slow pages Content problems
THE DIAGNOSTIC ORDER
Does it resolve? If yes, DNS is fine. Does it resolve correctly? If yes, DNS is fine. Then look at the server, the application, or the certificate.
WHAT TO TELL US
The result of that lookup. It saves a round trip.
