net-opslisted

# Network Operations Diagnose network problems on Windows, macOS, or Linux with a layered ladder that isolates faults to the smallest possible scope, then pattern-match against OS-specific culprits. Designed for the common case: someone reports "internet broken" on a box you can shell into (locally or via SSH). ## The Universal Insight **Bypass-tool succeeds while OS-resolver fails is a smoking gun on every platform.** It means DNS infrastructure is healthy but the operating system's name-resolution path is hooked or misconfigured. The bypass tool differs per OS but the discriminator is identical: | OS | Bypass tool | OS resolver tool | If bypass works but resolver fails | |---|---|---|---| | Windows | `nslookup` | `Resolve-DnsName`, browsers | NRPT, WFP, HOSTS, LSP, local 127.0.0.1:53 proxy | | macOS | `dig @1.1.1.1` | `dscacheutil -q host`, browsers | `/etc/resolver/*`, scutil DNS, profiles, mDNSResponder, kext | | Linux | `dig @1.1.1.1` | `getent hosts`, `resolvectl query` | systemd-resolved, `/etc/resolv.conf`, NetworkManager, dnsmasq, NSS | The bypass tool implements its own resolver and talks straight to UDP/53. The OS resolver tool goes through the full system name-service path including all hooks. Comparing the two narrows the suspect list dramatically. ## The Diagnostic Ladder Walk down the layers in order. **Do not skip rungs.** Each rung has a binary outcome that eliminates everything above it. Per-OS tools are in `references/diagnostic-ladder.md`; the struc