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Networking

Networking

Networking is the plumbing that carries every request between a visitor and your server: DNS that turns a name into an address, TLS that encrypts the connection, the routing and edge that move bytes fast, and the proxies and firewalls in between. When it works you never think about it; when it breaks it produces the strangest bugs, a site that loads in one browser and not another, a 520 that no log explains, a certificate that expired at the worst moment. Understanding the layers, what resolves a domain, what terminates encryption, what limits a connection, is what lets you fix the problem at its source instead of guessing. These notes come from chasing real network failures across real infrastructure: the header that broke one browser, the DNS change that took a day to propagate, and the routing fix that quietly held everything together.

8 pieces

All of the Journal
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Push Your CDN Cache Hit Ratio Past 95 Percent

Stale-while-revalidate, surrogate keys, and origin-shield patterns that keep traffic off your servers and pages near instant.

7 min read
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Serve Unlimited Subdomains From One Cloudflare Origin Certificate

Use a wildcard SAN origin cert behind Cloudflare so every new subdomain goes live without minting or renewing a certificate.

7 min read
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How Anycast DNS Cuts Resolver Latency Without Adding Servers

Why one IP answered from dozens of cities beats regional nameservers, and how to verify with dig and NSID that it routes close.

7 min read
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TLS 1.3 Zero Round Trip Resumption and the Replay Risk It Hides

0-RTT shaves a round trip off reconnects, but ship it wrong and you invite replayed POSTs; here is exactly where the line is.

7 min read
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Why Your Site Returns 520 in Safari but Works in Chrome

Safari coalesces cookies into one HPACK field that trips nginx 1.18 limits, so Cloudflare returns an untraceable 520. Two lines fix it.

7 min read
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Set DNS TTLs So Failover Is Instant Without Hammering Resolvers

Short TTLs reroute traffic in seconds but multiply query load. Set TTL per record by volatility, and lower it before any planned cutover.

7 min read
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Expose an Internal App Publicly Without Opening a Single Port

Cloudflare Tunnel reaches out from your server instead of letting the world reach in, so your origin IP and firewall stay invisible.

7 min read
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Route Every User to Their Nearest Region With Latency Based DNS

Serve the closest healthy origin automatically so a user in Accra and one in Frankfurt both get a fast first byte.

7 min read

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