Somebody on the network team pulls a capture off the guest wifi, filters for TLS, and half the hostnames are gone. The Android half. That is Android 17 doing what...
Read moreDetailsSomewhere between Gaithersburg and College Park there's a strand of ordinary telecom fiber hanging off utility poles, doing what fiber on poles does: swaying in wind, stretching in the afternoon...
Read moreDetailsSo NVIDIA put a 102.4-terabit-per-second Ethernet switch on stage on July 21, and the number is doing a lot of heavy lifting. Here's the short answer: Spectrum-6 roughly doubles the...
Read moreDetailsYou push a DNS change, then sit there wondering if it actually took. Don't wonder, ask: nslookup example.com works on any OS, Windows included, and confirms a name resolves or...
Read moreDetailsSomeone on the phone asks for your IP, and you blank on which command your OS wants. Windows takes ipconfig; Linux wants ip addr, or just ip a if you're...
Read moreDetailsThe new server is up, the IP is sitting in your clipboard, and the OVH panel is doing its best to hide the one tab you need. It's the DNS...
Read moreDetailsYou fixed the DNS record, and your Linux box keeps serving the old IP anyway. On modern Ubuntu, Debian and Fedora the fix is sudo resolvectl flush-caches, because systemd-resolved is...
Read moreDetailsA site moved servers yesterday and your PC keeps loading the old one. That's the Windows DNS cache holding a stale answer, and one command clears it: open Command Prompt...
Read moreDetailsSomeone asks for the WiFi password and you realize you typed it once, two years ago, and it's gone from your head. Your PC hasn't forgotten: one netsh command prints...
Read moreDetailsYou changed the record an hour ago, and half the office still lands on the old server. That's DNS TTL: the number of seconds a resolver may cache a DNS...
Read moreDetailsStéphane Cardon, network cybersecurity engineer. Architecture, LAN and WLAN, system administration. PacketNebula holds the tools and answers he wanted for his own work.
Copyright © 2026 Stephane Cardon.
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