How robust is DNSFilter's network infrastructure?

DNSFilter supports a technology called eDNS0 Client Subnet (ECS) – When we receive a request from you, we note your public source IP; and we pass along the /24 of that to the authoritative DNS of Office365. They then use that information in order to provide us with the ‘best’ location of theirs for YOU, regardless of where our anycast node that your traffic went to is located. So it’s then on them to have provided the best location based on your ISP and connectivity between your ISP and them.