Recently I stumbled across a nice website for monitoring live DNS requests:
Similar in concept to other websites designed for monitoring webhook data such as webhook.site, or BurpSuite more generally, pingb.in is a ready-made solution for DNS exfiltration so you don’t have to roll your own. Whilst it seems designed originally for capturing ICMP pings with a unique payload, it works great for DNS and HTTP too. Unfortunately it doesn’t seem to support HTTPS for some reason.
Keep it in mind the next time you need some quick DNS exfil!