Enabling BBR Congestion Control on Linux

If you’re running a server that handles long-distance TCP connections, switching from the default Cubic to BBR can make a noticeable difference in throughput. What is BBR? BBR (Bottleneck Bandwidth and Round-trip propagation time) is a congestion control algorithm developed by Google. Unlike loss-based algorithms like Cubic, BBR tries to model the actual bottleneck bandwidth and RTT, leading to better performance on lossy or high-latency links. Check Current Algorithm sysctl net.ipv4.tcp_congestion_control Most modern kernels default to cubic. ...

February 8, 2026 · 2 min · Du Song

Getting Started with WireGuard on Debian 12

WireGuard has become my go-to VPN solution for connecting remote machines. It’s fast, simple, and the configuration is refreshingly minimal compared to OpenVPN or IPSec. Why WireGuard? After years of wrestling with OpenVPN configs, WireGuard feels like a breath of fresh air: Performance: Runs in kernel space, significantly less overhead Simplicity: A single config file per interface Modern cryptography: ChaCha20, Curve25519, BLAKE2s — no cipher negotiation headaches Small codebase: ~4,000 lines of code vs. OpenVPN’s ~100,000+ Installation On Debian 12 (Bookworm), WireGuard is available directly: ...

January 15, 2026 · 2 min · Du Song