Umbrella/OpenDNS's global distribution of DNS servers supports huge caching of DNS lookups and enables us to store those lookups for the full Time-to-Live (TTL).
TTL is set by domain owners and tells recursive servers how long they may cache a resolved location before asking the authoritative nameservers once again where the domain points.
If you are a domain owner that is moving a domain from one host to another or just visiting a site that isn't resolving correctly, OpenDNS has a helpful tool that allows you to check the cache on our global resolvers. This tool is called CacheCheck and is available free at the following URL: https://cachecheck.opendns.com/
For domain owners:
OpenDNS gives you unique insight and control into how OpenDNS resolves your domain with OpenDNS CacheCheck. If you are moving a domain from one DNS host to another, CacheCheck can help you make that transition smoother. In effect, you tell OpenDNS to "refresh now," ahead of Time-To-Live (TTL) expiration.
For website visitors:
If you visit a domain and find that it's not resolving, CacheCheck is a way for you to learn more about why that might be happening. In some cases, you can help fix the problem even though you don't control the domain itself.
How to use the CacheCheck tool
If there's anything amiss with a certain domain, you can always refresh OpenDNS's cache for the domain using this tool. The steps to do so are very easy and are as follows:
Visit the CacheCheck site at https://cachecheck.opendns.com
Enter a domain name to check and select the "Check this domain" button.
If you haven't used the CacheCheck recently, you might be presented with a Captcha prompt. Please enter the code from the image next to the input box.
Your results will then be displayed as below:
If you notice an IP discrepancy with any of our resolvers, scroll down to the very bottom of the screen and press the "Refresh the Cache".
That's it! If successful, you will see the following message: "All locations returned the same (valid) answer. If the refreshed results look good, you're done! Our cache now has the correct answers for your domain."
If you are still running into issues with an IP resolving correctly on one or more of our servers, please provide us with the following diagnostic tool results and contact one of our support engineers at firstname.lastname@example.org for help.