lnstat
lnstat is a unified Linux network statistics tool that periodically displays statistical values exported by the kernel. A feature-complete replacement for the old rtstat program, lnstat reads from /proc/net/stat/ files to present routing cache statistics, neighbour table cache, and other kernel-level network metrics in a configurable, human-readable format. It is part of the iproute2 package, the standard Linux networking toolkit.
Key Features
- Kernel statistics — Reads and displays network statistics from /proc/net/stat/* files
- Selective display — Choose which statistics to show with the -s option
- Custom intervals — Configurable update interval and display width
- Colour-coded output — Colour highlighting for easier visual parsing
- Wide range of stats — Supports routing cache, ARP cache, neighbour table, and other kernel network statistics
- rtstat replacement — Generalised drop-in replacement with extended capabilities
- Part of iproute2 — Pre-installed on virtually all Linux distributions
Why Use It
lnstat provides low-level visibility into the kernel’s network internals that no other tool offers. While tools like iftop and nload show application-level traffic rates, lnstat exposes the kernel’s own routing cache and neighbour table statistics — essential for understanding how the network stack behaves under load and diagnosing routing or ARP issues.
Use Cases
- Routing cache analysis — Monitor kernel routing cache hit/miss ratios to evaluate routing performance
- ARP/neighbour table monitoring — Track neighbour cache entries and detect table overflow
- Network stack diagnostics — Understand how kernel forwarding and filtering performance changes under load
- Real-time kernel stats — Watch kernel network statistics update live for debugging and tuning
Platform
Linux
Licence
GNU General Public License v2.0