Thanks for your comment. > Have any of your test users been behind corporate firewalls yet? I ask because there are some corporate firewalls (Fortigate, PAN to

Thanks for your comment. > Have any of your test users been behind corporate firewalls yet? I ask because there are some corporate firewalls (Fortigate, PAN to name a couple) that will see excessive DNS requests as a denial of service attack. We've done some limited testing with this on a protocol level but there's lots more to do. This example site uses DoH which some firewalls just straight up block, in that case this site and associated client-side libraries wouldn't function at all. If a connection to Cloudflare DoH is made successfully, then it's unlikely any of this traffic will be troubled by the firewall since it's just over HTTPS. > What are the max queries per second this implementation can trigger per client? This example implementation is only limited by the browser and Cloudflare. In the Barclays example link provided it's sending 56 DNS queries in around a second. This is a pretty heavy implementation, a NUM lookup for a URL like num://numexample.com:1 only requires upto 2 DNS queries. The reason this implmentation is so heavy is that we're combining a whole bunch of records.