Balancing hardening and speed is like fine‑tuning a kernel—tweak the defaults, then measure. Start with a minimal initramfs, lock down sysctl: no IP forwarding, disable send‑redirects, tighten tcp\_syncookies, and turn off unused services. Use nftables or iptables to drop obvious bad packets but keep the rule set lean; one complex rule is slower than ten simple ones. For binaries, strip symbols, enable PIE and ASLR, and use seccomp‑bpf to sandbox. Keep a log of latency changes; if a rule drops a ping by 5ms, question it. Remember, a server that breathes faster is safer if the breath is controlled. And hey, if you see a process running with a huge memory footprint, just tell it to stop—performance is not a mystery, it’s a puzzle waiting for the right pieces.