Found a really helpful repo to make ESP32 act as DNS server.
/* * ---------------------------------------------------------------------------- * "THE BEER-WARE LICENSE" (Revision 42): * Jeroen Domburg <jeroen@spritesmods.com> wrote this file. As long as you retain * this notice you can do whatever you want with this stuff. If we meet some day, * and you think this stuff is worth it, you can buy me a beer in return. * * modified for ESP32 by Cornelis * * ---------------------------------------------------------------------------- */ /* This is a 'captive portal' DNS server: it basically replies with a fixed IP (in this case: the one of the SoftAP interface of this ESP module) for any and all DNS queries.