Hello Apple Developer Community, I am currently working on a macOS project where my primary goal is to intercept IP packets, modify them (specifically the TCP payload), and then forward them. My intended use case involves selectively intercepting outgoing packets based on their destination IP, altering their content, and sending them on their way to the original destination. What I’ve Tried: NEAppProxyProvider: • I explored using App Proxy Provider to handle new TCP and UDP flows. • While it allowed me to read the data, handling direct packet modification and forwarding without creating a new connection or proxy setup proved challenging, especially for maintaining TCP state and handling TLS traffic. System Extension with NEFilterPacketProvider: • I considered NEFilterPacketProvider for intercepting and modifying network packets. • However, the documentation implies that packet filtering only supports allow/block actions, not modification and reinjection of packets back into the system. I am planning to try NEPacketTunnelProvider: But the documentation states that this is not the right use case. Packets are expected to go into the tunnel. Since I don't have any requirement to create and maintain a tunnel, this doesn't look like an option for me. Transparent proxy setups like NETransparentProxyProvider do not appear to offer direct packet modification capabilities without involving a user-space proxy approach. Implementing packet-level interception outside of the Network Extension framework (e.g., Network Kernel Extension) seems unsupported in newer macOS versions (Sequoia and later). My Questions: Is there a recommended approach or combination of Network Extension capabilities that would allow intercepting and modifying IP packets directly? Can NEFilterPacketProvider or any other extension be utilized in a way to modify and reinject packets back into the system? Are there any examples or sample projects that achieve similar functionality, possibly using a blend of Network Extension and lower-level networking frameworks? I appreciate any insights or pointers to documentation or examples that could help achieve this. Thanks and Regards. Prasanna.