No, this is on iOS. The goal is to drop specific DNS packets on iOS, while forwarding all other packets through a local socket. However, it currently seems impossible to achieve this on iOS. So far, I’ve only managed to forward UDP packets. For other protocols, I haven’t found a way to capture the full IP packet, making it impossible to reconstruct the IP packet correctly.

I found that the TUN interface was actually writing back correctly. It seems that Xcode was just displaying incorrect information. Although Xcode showed 0.0.0.0:0 and no packets being read or written on that interface, it was likely just an issue with Xcode not displaying the correct interface properly.