Networking Bundle

Networking Bundle

Three cheatsheets covering the networking tools every engineer reaches for: Nginx for TLS termination and reverse proxying, SSH for secure remote access and tunneling, and the diagnostic toolbox — curl, ss, tcpdump, dig, mtr — for finding faults when traffic doesn't flow.

What's Included

Nginx Cheatsheet

• Server blocks — name-based routing, default server behaviour
• Reverse proxy patterns — proxy_pass, headers, buffering, timeouts
• TLS configuration — modern ciphers, OCSP stapling, HSTS, redirect chains
• Load balancing — upstream pools, health checks, session persistence
• Rate limiting and caching — limit_req zones, proxy_cache validity
• Debugging — error log levels, stub_status, $status access-log analysis

SSH Cheatsheet

• Key management — ed25519 generation, agent forwarding, known_hosts hygiene
• Client config — per-host settings, jump hosts (ProxyJump), multiplexing
• Tunnels — local, remote, and dynamic forwarding with concrete examples
• Hardening — disable password auth, restrict keys via authorized_keys options
• File transfer — scp vs rsync, checksumming, partial transfers

Network Tools Cheatsheet

• ss/netstat — socket states, listening ports, per-process attribution
• curl — verbose output, timing breakdown, retry logic, HTTP/2 testing
• tcpdump — capture filters, reading handshakes, common failure signatures
• dig/nslookup — DNS resolution paths, TXT records, propagation checks
• mtr/traceroute — latency and loss per hop, asymmetry detection
• iperf3 — throughput testing, parallel streams, UDP mode

Excerpt — Nginx Reverse Proxy with Timeouts

Proxy timeouts cause more mystery 502s than any other misconfiguration. Production defaults should be explicit:

location / {
    proxy_pass http://app:3000;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;

    # Match these to your app's worst-case response time
    proxy_connect_timeout 5s;
    proxy_read_timeout    60s;
    proxy_send_timeout    60s;
}

Excerpt — Reading Connection States with ss

# Which process listens on 443?
ss -tlnp 'sport = :443'

# Count connections per state — a TIME_WAIT flood shows here first
ss -tan | awk '{print $1}' | sort | uniq -c

# Established connections from a specific subnet
ss -tn state established '( dst 10.0.1.0/24 )'

Finding the Layer That's Broken

| Symptom | First tool | What to look for | |---|---|---| | Domain doesn't resolve | dig | NXDOMAIN vs SERVFAIL, authoritative answers | | Connects but no response | curl -v | TLS handshake vs request hang | | Intermittent slowness | mtr | Loss at a specific hop | | Port unreachable | ss | Nothing listening, or wrong bind address | | 502 from proxy | nginx error log | upstream timeout vs connection refused |

The tools sheet is organized around this diagnostic flow — symptom first, tool second.

Related Reading on graphwiz.ai

• IDS Frameworks Compared: Host vs Network Detection

Format

• Three PDFs (print-ready, A4)
• Instant download after purchase

Price

$9.00

Who This Is For

• Backend and DevOps engineers configuring reverse proxies, load balancers, and secure SSH access
• System administrators managing network troubleshooting and performance analysis
• Anyone deploying web applications who needs to understand TLS termination, SSH tunneling, and network diagnostics

FAQ

Does the Nginx sheet cover Caddy or Traefik? No — it targets Nginx specifically. If you run Traefik with Docker, the AI Infrastructure Mastery guide covers Traefik config in depth.

Are the SSH sections OpenSSH-specific? Yes, OpenSSH 9.x. Windows clients via native OpenSSH work identically; PuTTY-specific workflows are not covered.

Are the cheatsheets updated? Yes — buyers get re-download access to new revisions through the library page.