UK Broadband ISP BT customers, especially those with one of the operator’s Mini Whole Home Wi-Fi systems (mesh repeaters) and custom DNS setup on their home network, were invited to expect a firmware fix again, after complaining that their connections were doing masses of DNS lookups to Google and Microsoft.
The existing Domain name system (DNS) works by converting Internet Protocol (IP) addresses to human readable form (eg 126.96.36.199 in examplezfakedomain.co.uk) and vice versa. In this context, a DNS lookup is the process by which a DNS record is returned from a DNS server (i.e. much like looking up a phone number in the phone book).
In February 2020, some BT customers started noticing that each of the operator’s mesh repeaters was sending masses of DNS lookup requests to Microsoft.com (here) – pretty much similar to a search per second per dish (some people have multiple dishes), and if they blocked them, the devices would just start doing the same for Apple.com so what Google FR etc.
The affected customers had all changed their network to use a custom DNS provider (e.g. OpenDNS, Google Public DNS, etc.) instead of BT, meaning that these DNS providers started flagging some of their connections as “”mistrustful“due to the unusual excess of DNS lookups (i.e. disrupting access to some internet services and causing more sites to check if you are a bot before granting access – captcha style).
At the time, BT had promised to release a firmware update to fix the problem, but according to The register it never materialized. The good news is that, more than a year later, such an update could finally arrive.
A BT spokesperson said:
“We understand how important connectivity is to our customers, and like other products on the market, BT Mini Whole Home Wi-Fi has built-in server queries to alert customers of any connection issues as quickly as possible. We recognize that there are a small number of customers who have personally set up a custom DNS server setup at home, and the frequency of these checks may cause them to see additional network traffic.
We have included an update in a new, larger firmware, which significantly reduces the frequency of these server requests. We had planned to deploy this earlier, but due to shifting priorities following the exceptional circumstances of last year, it took longer than expected. We apologize to the small number of customers affected by this matter. “
No doubt Microsoft, Apple and Google will greatly appreciate BT doing massive DNS lookups to help identify connection issues with the carrier’s broadband and WiFi kit. The question now is, when will the new firmware actually surface? Affected customers have already been waiting for over a year.