udp2raw-tunnel is a tunneling tool that converts UDP traffic into encrypted UDP, FakeTCP, or ICMP packets using raw sockets to bypass UDP firewalls and improve reliability in unstable network environments.
The tool addresses the problem of UDP traffic being blocked, throttled, or behaving unpredictably on certain networks. It solves this by wrapping UDP packets in alternative protocol headers that firewalls are less likely to restrict. In FakeTCP mode, it simulates a real TCP connection with handshakes and sequence numbers while maintaining UDP's real-time delivery characteristics, avoiding the TCP-over-TCP problem that occurs when tunneling TCP-based protocols like OpenVPN over actual TCP connections. ICMP mode disguises traffic as ping packets. The tool encrypts payloads with AES-128-CBC, protects integrity with HMAC-SHA1, and defends against replay attacks. It detects connection failures through heartbeats and automatically reconnects by changing port numbers while preserving existing UDP conversations.
Developers should choose this tool if they need to route UDP-based services through restrictive networks or want to combine it with a UDP VPN like OpenVPN or L2TP to tunnel any traffic type. It works on Linux systems with root access or raw socket capabilities, including embedded platforms like OpenWRT routers and Raspberry Pi. The tool requires no external dependencies and includes precompiled binaries for common platforms. Windows and macOS users should use the multiplatform variant. When used alone, udp2raw only tunnels UDP traffic, but pairing it with a UDP VPN enables tunneling of TCP, UDP, and ICMP together.
Development activity shows consistent maintenance with bug fixes and feature refinements applied regularly. The project maintains comprehensive documentation including a wiki with encryption notes and platform-specific guidance. Cross-compilation is straightforward, requiring only a toolchain and makefile modification. The codebase demonstrates stability through testing on diverse environments including OpenVZ-based VPS providers.
