Playbooks
The concept behind the command
Every playbook here is built into the tool — n -h <name> prints the same text offline. These are the traps and the root causes: why a mapped drive vanishes in an admin window, why a Linux CIFS mount is owned by root, what NTFS and share permissions do to each other.
Cross-Platform Networking
n -h linux-cifs
Linux CIFS / SMB Mounts & The Root Ownership Trap
Preventing 'Permission Denied' on Linux CIFS mounts caused by missing uid/gid options, and configuring secure /etc/fstab credentials files.
n -h linux-nfs
Linux NFS Exports, Root Squashing & Port Requirements
Understanding root_squash vs no_root_squash (UID 65534 nobody), NFSv3 vs NFSv4 port requirements (RPC 111, NFS 2049), and firewall rules.
n -h macos-smb
macOS SMB Speed Throttling & Network Share File Pollution
Resolving 10x SMB throughput drops caused by mandatory packet signing (/etc/nsmb.conf) and preventing .DS_Store / AppleDouble pollution.
Diagnostics
Networking concepts
n -h arp
ARP and MAC addresses — layer 2, the vendor tell, and stale neighbours
An ARP entry proves a device is on your physical LAN. No entry means it's elsewhere — a VLAN, a VPN, another subnet — or asleep.
n -h cgnat
CGNAT — why you can't port-forward, and what to do instead
Carrier-grade NAT shares one public address among many customers. Inbound connections can't reach you; Tailscale or a tunnel can.
n -h dns
DNS — names to addresses, and the caches that lie
"It pings by IP but not by name" is always DNS. The answer can come from five layers, and each one caches — including the answer 'no'.
n -h gw
Default gateway — the router, and the route to everything else
Every packet that isn't for your own subnet goes to the gateway. No route, or no reply, and the internet is unreachable no matter what else works.
n -h hops
Hops and TTL — how many routers away, and what the TTL gives away
Every router a packet crosses decrements its TTL. From the reply's TTL you can count the hops and usually name the remote OS.
n -h http
HTTP status codes and the Server header — what a web port is telling you
A three-digit code and one header say whether a web service is healthy, redirecting, locked, or broken — before you open a browser.
n -h ipv6
IPv6 — dual-stack, what 'inactive' means, and the one thing to watch
Native IPv6 is a bonus, not a requirement. Half-working IPv6 is worse than none — that's the case to recognise.
n -h loop
Loopback — 127.0.0.1 and the kernel's own network stack
The first check in every ladder: can this machine talk to itself? If not, no cable in the world will help.
n -h port-states
Port states — open, closed, filtered, and what the common ports mean
A TCP port can answer three ways. Each one tells you something different about the host, its firewall and what's running.
n -h rtt
RTT — latency, what the numbers mean, and why 'no reply' isn't 'down'
Round-trip time decides how snappy everything feels, far more than bandwidth does for small files, SSH and web pages.
n -h tls-certificates
TLS certificates — issuer, expiry, self-signed, and what to do before it lapses
netscrew reads the certificate on every HTTPS port it finds and counts down to expiry. Here's what the fields mean and when to worry.
n -h wan
WAN — is the internet actually reachable?
Pinging 1.1.1.1 and 8.8.8.8 by address separates 'the internet is down' from 'names don't resolve'. If this passes and DNS fails, it's DNS.
Storage & Diagnostics
Storage & Permissions
n -h ntfs-acls
Windows Share Permissions vs. NTFS Permissions (The Intersection Trap)
Why 'Everyone: Full Control' on an SMB share still yields 'Access Denied', how Share ACLs intersect with NTFS ACLs, and ICACLS remediation.
n -h uac-shares
Windows UAC Mapped Drive Isolation & EnableLinkedConnections
Why network drives mapped in elevated admin prompts vanish from Windows Explorer, and how EnableLinkedConnections links them.
System & Hardware
n -h disk
Storage Capacity, Health Thresholds & Filesystem Triage
Disk usage warning (>80%) and critical (>95%) thresholds, SSD endurance, TRIM, Linux inode exhaustion (df -i), and NTFS dirty bit recovery.
n -h sys
System & Hardware Diagnostics Playbook
Decoding hardware DMI, CPU core utilization spikes, RAM module MT/s transfer rates and dual-channel verification, and GPU driver detection.