What's ISP Cached DNS Lookup ? This tool lets you look up a DNS record at the DNS servers of many popular Internet providers. This lets you see which one(s) have
cached DNS entries. That way, if you just made a DNS change, you can see when major ISPs will detect the change. Note that this test is specially designed so that it instructs the DNS server not to add the DNS record to its cache, if it is not already there (so future lookups will not be spoiled).