I've implemented a custom VPN for macOS (system extension, Packet Tunnel Provider). My question is related to the tunnel's DNS servers: I would like that even when a split-tunnel is enabled, all DNS queries will reach the tunnel's DNS, but I'm aware that this case is not 'working well', and the Packet Tunnel Provider is not supposed to capture all DNS queries, see those threads:https://developer.apple.com/forums/thread/662443, https://developer.apple.com/forums/thread/661601 So as a workaround, on a split-tunnel I have a list of 'match domains', and 'search domains'. But now it seems that the default interface will answer those queries as well, and they still won't reach the tunnel's DNS. To verify this, I connected with the VPN, and when I checked 'scutil --dns', I got the list of resolvers, where resolver #1, wasn't the utun (it was en7), and it handled all the 'match domain'/'search domains'. Any idea how to force some/add DNS queries to the tunnel's DNS even when for a split tunnel?

[Network Extension, Packet Tunnel Provider, iOS, split tunnel] I've implemented a custom network extension app for iOS using Packet Tunnel Provider. A customer enabled a split tunnel, set the tunnel's DNS servers, and added relevant 'search domains' and 'match domains'. Then, he reported an error related to DNS, specifically, DNS Over HTTPS. He noticed that DNS queries were sent over HTTPS. He also has the corresponding app for Mac (Packet Tunnel Provider, macOS, system extension), and everything works fine with the same DNS configuration, and the DNS queries were sent as a 'clear text', not DoH. Is DoH the default behavior on iOS? Is it the default on macOS? Can we somehow change this behavior? Are DoH queries reach the tunnel as plain DNS queries?

Is it possible to have both 'includeAllNetworks' and split-tunnel simultaneously? I want to enable a split tunnel so only some of the traffic will reach the tunnel, but at the same time, to make sure that the above traffic will always reach the tunnel - even if it's coming from some low-level networking API or even if the traffic started before creating the tunnel. Setting the 'includeAllNetworks' flag will help with the above cases, but then I'll get all the traffic via the tunnel without consideration in the split tunnel configuration. (Details: System-extension, PacketTunnelProvider)

I've implemented a custom system extension VPN for macOS, using a Packet Tunnel Provider. I saw something suspicious on macOS 15.2.0: When I disconnected my VPN, the UTUN was not being cleared. This results in a lot of UTUNs when the user connects and disconnects multiple times. utun77: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500 utun78: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500 This happens only on macOS 15.2. I tried the same app on older versions (15.0, 15.1.x), and it didn't reproduce. Can those 'dirty' UTUNs cause a networking problem? Since it happens only on macOS 15.2, is there a bug in this OS version? How can I check if something in my code causes this behavior? How can I 'fix' it or force clean the 'dirty' UTUNs?