I was wondering how exactly the pre-cloud Blokada app worked and if the source code of it is public. I specifically need the iOS and pre-cloud version code. I was doing some pentesting at a local school and noticed that when changing the DNS directly on an iPhone, the DNS-based blocking worked and stopped them from viewing restricted content, however, with the old version of Blokada, they completely bypassed it and searched the web unfiltered. If anyone can provide a description of how it worked in depth or the source code itself, it would be greatly appreciated.
The first version on iOS worked similar to v5 for Android, by configuring a fake VPN service you can set which DNS server to use.
Blokada v6 configures DNS via the new encrypted DNS over HTTPS and should have the same effect regarding bypassing said filters at your school. It sounds like they do DNS based filtering, simply changing the DNS will bypass these filters