.. 제목: Linux TCP Sysctl 튜닝 참조
.. 슬러그: linux-tcp-sysctl-reference
.. 날짜: 2026-03-27 12:00:00 UTC
.. 태그: 리눅스, TCP, sysctl, 성능, 커널, 계산기, 도구
.. 카테고리: 계산기
.. 링크:
.. 설명: 대량 전송, 대기 시간에 민감한 RPC, 높은 연결 웹 서버 및 긴 파이프 WAN을 위한 워크로드 사전 설정이 포함된 대화형 Linux net.ipv4.tcp_* 및 net.core.* 매개 변수 가이드입니다.
.. 유형: 텍스트
<style>
/* ── CANONICAL DESIGN SYSTEM ──────────────────────────────────────────────── */
.calc-container { max-width: 900px; margin: 20px auto; padding: 20px; }
.calc-header { margin-bottom: 30px; padding: 25px; background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); border-radius: 12px; box-shadow: 0 4px 6px rgba(0,0,0,0.1); color: white; }
.calc-header h2 { margin-top: 0; color: white; font-size: 28px; margin-bottom: 10px; }
.calc-header p  { margin: 10px 0; opacity: 0.95; font-size: 15px; }
.input-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 15px; margin-top: 20px; }
.input-group { display: flex; flex-direction: column; }
.input-group label { margin-bottom: 8px; font-weight: 600; color: rgba(255,255,255,0.95); font-size: 14px; }
.input-group input, .input-group select, .input-group textarea { padding: 14px; font-size: 14px; border: 2px solid rgba(255,255,255,0.3); border-radius: 6px; background: rgba(255,255,255,0.95); transition: all 0.3s ease; box-sizing: border-box; font-family: inherit; }
.input-group input:focus, .input-group select:focus, .input-group textarea:focus { outline: none; border-color: #4CAF50; background: white; box-shadow: 0 0 0 3px rgba(76,175,80,0.1); }
.button-container { margin-top: 20px; display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; }
.calc-button { padding: 14px 35px; font-size: 16px; background: #4CAF50; color: white; border: none; border-radius: 6px; cursor: pointer; font-weight: bold; transition: all 0.3s ease; box-shadow: 0 2px 4px rgba(0,0,0,0.2); }
.calc-button:hover  { background: #45a049; transform: translateY(-1px); box-shadow: 0 4px 8px rgba(0,0,0,0.3); }
.calc-button:active { background: #3d8b40; transform: translateY(0); }
.calc-button.secondary { background: rgba(255,255,255,0.2); }
.calc-button.secondary:hover { background: rgba(255,255,255,0.3); transform: translateY(-1px); }
.result-section { background: white; border: 1px solid #e0e0e0; border-radius: 8px; margin-top: 20px; overflow: hidden; box-shadow: 0 2px 4px rgba(0,0,0,0.05); transition: all 0.3s ease; }
.result-section:hover { box-shadow: 0 4px 8px rgba(0,0,0,0.1); }
.section-header { background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%); color: white; padding: 15px 20px; font-size: 18px; font-weight: bold; }
.section-content { padding: 20px; background: #fafafa; }
@media (max-width: 768px) { .input-grid { grid-template-columns: 1fr; } .calc-header h2 { font-size: 22px; } .calc-container { padding: 10px; } }

/* Page-specific */
.filter-row { display: flex; gap: 10px; flex-wrap: wrap; }
.preset-row { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 16px; }
.preset-btn { padding: 10px 16px; background: rgba(255,255,255,0.2); border: 2px solid rgba(255,255,255,0.4); border-radius: 6px; cursor: pointer; font-size: 14px; font-weight: 600; color: white; transition: all 0.3s ease; }
.preset-btn:hover { background: rgba(255,255,255,0.3); border-color: rgba(255,255,255,0.6); }
.preset-btn.active { background: #4CAF50; border-color: #4CAF50; }
.param-card { background: white; border: 1px solid #e0e0e0; border-radius: 8px; margin-bottom: 10px; overflow: hidden; }
.param-header { padding: 12px 16px; cursor: pointer; display: flex; align-items: center; justify-content: space-between; background: #fafafa; border-bottom: 1px solid #eee; flex-wrap: wrap; gap: 8px; }
.param-header:hover { background: #f0fff0; }
.param-name { font-family: 'Courier New', monospace; font-weight: bold; color: #2d6a2d; font-size: 14px; }
.param-value { font-family: 'Courier New', monospace; font-size: 13px; color: #155724; background: #d4edda; padding: 3px 8px; border-radius: 4px; }
.param-tag { font-size: 11px; padding: 2px 8px; border-radius: 10px; background: #4CAF50; color: white; font-weight: bold; margin-right: 4px; }
.param-body { padding: 14px 16px; display: none; font-size: 13px; line-height: 1.6; }
.param-body.open { display: block; }
.param-meta { display: flex; gap: 16px; flex-wrap: wrap; margin-top: 8px; font-size: 12px; color: #666; }
.copy-block { background: #1e1e2e; color: #cdd6f4; padding: 8px 12px; border-radius: 6px; font-family: 'Courier New', monospace; font-size: 12px; margin: 8px 0; position: relative; }
.copy-btn { position: absolute; top: 6px; right: 8px; background: #4CAF50; color: white; border: none; border-radius: 4px; padding: 2px 8px; font-size: 11px; cursor: pointer; }
.copy-btn:hover { background: #45a049; }
.tag { display: inline-block; background: #e8f5e9; color: #2d6a2d; padding: 2px 7px; border-radius: 10px; font-size: 11px; margin-right: 4px; }
code { background: #f0f0f0; padding: 2px 5px; border-radius: 3px; font-family: 'Courier New', monospace; font-size: 12px; }
.copy-all-btn { display: block; margin-top: 10px; padding: 12px 20px; background: #4CAF50; color: white; border: none; border-radius: 6px; cursor: pointer; font-size: 14px; font-weight: bold; transition: all 0.3s ease; }
.copy-all-btn:hover { background: #45a049; transform: translateY(-1px); }
@media (max-width: 768px) { .param-header { flex-direction: column; align-items: flex-start; } .preset-row { gap: 8px; } }
</style>
<div class="calc-container">
<div class="calc-header">
<h2>Linux TCP Sysctl 튜닝 참조</h2>
<p>인터랙티브<code style="color:rgba(255,255,255,0.9)">net.ipv4.tcp_*</code>그리고<code style="color:rgba(255,255,255,0.9)">net.core.*</code>대량 전송, 대기 시간에 민감한 RPC, 고연결 웹 서버 및 긴 파이프 WAN을 위한 워크로드 사전 설정이 포함된 매개변수 가이드입니다.</p>
<div class="input-grid">
<div class="input-group">
<label>검색/필터</label>
<input id="searchInput" oninput="filterParams(this.value)" placeholder="Search parameters..." type="text"/>
</div>
<div class="input-group">
<label>워크로드 사전 설정</label>
<div class="preset-row" id="presetRow"></div>
</div>
</div>
</div>
<div class="result-section">
<div class="section-header">TCP Sysctl 매개변수</div>
<div class="section-content" id="paramList">
</div>
<div style="padding: 20px; background: #fafafa; border-top: 1px solid #e0e0e0;">
<button class="copy-all-btn" onclick="copyAll()">표시된 모든 매개변수를 sysctl 명령으로 복사</button>
</div>
</div>
</div>
<script>
const PARAMS = [
    {
        name: 'net.ipv4.tcp_rmem',
        desc: 'TCP receive buffer sizes: min, default, max (bytes). Kernel auto-tunes between min and max.',
        default: '4096 131072 6291456',
        presets: {
            bulk: '4096 131072 134217728',
            rpc: '4096 87380 4194304',
            web: '4096 131072 16777216',
            wan: '4096 131072 134217728',
        },
        range: 'min 4096; max up to ~1GB (limited by net.core.rmem_max)',
        tags: ['buffer', 'receive', 'window'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.ipv4.tcp_wmem',
        desc: 'TCP send buffer sizes: min, default, max (bytes).',
        default: '4096 16384 4194304',
        presets: {
            bulk: '4096 16384 134217728',
            rpc: '4096 16384 4194304',
            web: '4096 16384 16777216',
            wan: '4096 16384 134217728',
        },
        range: 'min 4096; max up to ~1GB',
        tags: ['buffer', 'send', 'window'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.core.rmem_max',
        desc: 'Maximum receive socket buffer size. Upper bound for tcp_rmem max.',
        default: '212992',
        presets: {
            bulk: '134217728',
            rpc: '4194304',
            web: '16777216',
            wan: '134217728',
        },
        range: '212992 – 2147483647',
        tags: ['buffer', 'receive', 'core'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.core.wmem_max',
        desc: 'Maximum send socket buffer size.',
        default: '212992',
        presets: {
            bulk: '134217728',
            rpc: '4194304',
            web: '16777216',
            wan: '134217728',
        },
        range: '212992 – 2147483647',
        tags: ['buffer', 'send', 'core'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.ipv4.tcp_congestion_control',
        desc: 'Default TCP congestion control algorithm.',
        default: 'cubic',
        presets: {
            bulk: 'bbr',
            rpc: 'cubic',
            web: 'bbr',
            wan: 'bbr',
        },
        range: 'cubic, bbr, reno, htcp (check: sysctl net.ipv4.tcp_available_congestion_control)',
        tags: ['congestion', 'bbr', 'cubic'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.ipv4.tcp_window_scaling',
        desc: 'Enable TCP window scaling (RFC 1323). Required for windows > 65535 bytes.',
        default: '1',
        presets: { bulk: '1', rpc: '1', web: '1', wan: '1' },
        range: '0 (disable) or 1 (enable)',
        tags: ['window', 'rfc1323'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.ipv4.tcp_timestamps',
        desc: 'RFC 1323 timestamps — used for PAWS (protection against wrapped sequence numbers) and RTT measurement.',
        default: '1',
        presets: { bulk: '1', rpc: '1', web: '1', wan: '1' },
        range: '0 (disable), 1 (enable), 2 (enable without ECR)',
        tags: ['rfc1323', 'paws', 'rtt'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.ipv4.tcp_sack',
        desc: 'Selective Acknowledgements (RFC 2018). Allows receiver to inform sender of non-contiguous received segments, improving recovery from multiple losses.',
        default: '1',
        presets: { bulk: '1', rpc: '1', web: '1', wan: '1' },
        range: '0 or 1',
        tags: ['sack', 'loss', 'recovery'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.ipv4.tcp_max_syn_backlog',
        desc: 'Maximum number of SYN packets queued per listening socket before dropping. Increase for high connection-rate servers.',
        default: '1024',
        presets: {
            bulk: '1024',
            rpc: '4096',
            web: '65536',
            wan: '1024',
        },
        range: '128 – 65536 (limited by system memory)',
        tags: ['syn', 'connection', 'backlog'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.core.somaxconn',
        desc: 'Maximum socket listen backlog (accept queue depth). Application must also set listen() backlog >= this value.',
        default: '4096',
        presets: {
            bulk: '4096',
            rpc: '8192',
            web: '65535',
            wan: '4096',
        },
        range: '128 – 65535',
        tags: ['connection', 'backlog', 'accept', 'core'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.ipv4.tcp_tw_reuse',
        desc: 'Allow reuse of TIME_WAIT sockets for new connections when safe (requires timestamps). Reduces port exhaustion under heavy connection churn.',
        default: '2',
        presets: {
            bulk: '2',
            rpc: '1',
            web: '1',
            wan: '2',
        },
        range: '0 (disable), 1 (enable for loopback), 2 (enable for all)',
        tags: ['time_wait', 'port', 'reuse'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
    {
        name: 'net.ipv4.tcp_fin_timeout',
        desc: 'Time (seconds) a socket stays in FIN_WAIT_2 state before being forcibly closed. Reduce to reclaim ports faster under high connection rates.',
        default: '60',
        presets: {
            bulk: '60',
            rpc: '15',
            web: '15',
            wan: '60',
        },
        range: '5 – 120 seconds',
        tags: ['fin', 'timeout', 'connection'],
        doc: 'https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html',
    },
];

const PRESETS = {
    default: { label: 'Kernel Defaults', desc: 'Show kernel default values' },
    bulk: { label: 'Bulk File Transfer', desc: 'Large BDP, maximize throughput over high-RTT links' },
    rpc: { label: 'Latency-Sensitive RPC', desc: 'Low-latency datacenter RPCs (Redis, gRPC, etc.)' },
    web: { label: 'High-Connection Web Server', desc: 'High connection rate, many short-lived connections' },
    wan: { label: 'Long-Fat-Pipe WAN', desc: 'High bandwidth × high RTT (satellite, cross-continental)' },
};

let currentPreset = 'default';
let searchQuery = '';

function init() {
    const row = document.getElementById('presetRow');
    Object.entries(PRESETS).forEach(([key, p]) => {
        const btn = document.createElement('button');
        btn.className = 'preset-btn' + (key === 'default' ? ' active' : '');
        btn.textContent = p.label;
        btn.title = p.desc;
        btn.onclick = () => setPreset(key);
        row.appendChild(btn);
    });
    renderParams();
}

function setPreset(key) {
    currentPreset = key;
    document.querySelectorAll('.preset-btn').forEach((b, i) => {
        b.classList.toggle('active', Object.keys(PRESETS)[i] === key);
    });
    renderParams();
}

function filterParams(q) {
    searchQuery = q.toLowerCase();
    renderParams();
}

function getVal(p) {
    return currentPreset === 'default' ? p.default : (p.presets[currentPreset] || p.default);
}

function renderParams() {
    const list = document.getElementById('paramList');
    const filtered = PARAMS.filter(p => {
        if (!searchQuery) return true;
        return p.name.toLowerCase().includes(searchQuery) ||
               p.desc.toLowerCase().includes(searchQuery) ||
               p.tags.some(t => t.includes(searchQuery));
    });

    if (!filtered.length) {
        list.innerHTML = '<p style="color:#999">No parameters match your filter.</p>';
        return;
    }

    list.innerHTML = filtered.map((p, idx) => {
        const val = getVal(p);
        const cmd = `sysctl -w ${p.name}=${val}`;
        const tags = p.tags.map(t => `<span class="param-tag">${t}</span>`).join('');
        const changed = currentPreset !== 'default' && val !== p.default;
        return `<div class="param-card">
            <div class="param-header" onclick="toggleCard(event)">
                <span class="param-name">${p.name}</span>
                <span class="param-value" ${changed ? 'style="background:#d4edda;color:#155724"' : ''}>${val}</span>
            </div>
            <div class="param-body">
                ${p.desc}
                <div class="param-meta">
                    <span><strong>Default:</strong> ${p.default}</span>
                    <span><strong>Range:</strong> ${p.range}</span>
                </div>
                <div style="margin-top:8px">${tags}</div>
                <div class="copy-block">${cmd} <button class="copy-btn" onclick="copyCmd('${cmd}')">Copy</button></div>
            </div>
        </div>`;
    }).join('');
}

function copyCmd(cmd) {
    navigator.clipboard.writeText(cmd).catch(() => {
        const ta = document.createElement('textarea');
        ta.value = cmd; document.body.appendChild(ta); ta.select(); document.execCommand('copy'); ta.remove();
    });
}

function copyAll() {
    const filtered = PARAMS.filter(p => {
        if (!searchQuery) return true;
        return p.name.toLowerCase().includes(searchQuery) || p.desc.toLowerCase().includes(searchQuery) || p.tags.some(t => t.includes(searchQuery));
    });
    const cmds = filtered.map(p => `sysctl -w ${p.name}=${getVal(p)}`).join('\n');
    copyCmd(cmds);
    alert(`Copied ${filtered.length} sysctl commands to clipboard.`);
}

function toggleCard(event) {
    const card = event.currentTarget.closest('.param-card');
    const body = card.querySelector('.param-body');
    body.classList.toggle('open');
}

init();
</script>