Why Dish Beats Netstat: A Lightweight Socket Monitoring CLI

Overview

Dish is a lightweight command‑line tool written in Go for monitoring socket connection states. It can be invoked manually or scheduled with cron to perform one‑off health checks without a persistent daemon.

Core Capabilities

Connection success : verifies that a target host and port are reachable (e.g., HTTP port 80).

Abnormal disconnect : detects connection‑refused, timeout or reset (RST) conditions.

Stale connections : reports half‑open states such as TIME_WAIT and CLOSE_WAIT.

Protocol Support

Dish works with IPv4 and IPv6 and supports both TCP and UDP, making it suitable for typical services such as web servers, databases, and DNS resolvers.

Advantages

Lightweight : no external libraries, minimal CPU and memory footprint.

Simple & efficient : focuses on single‑shot socket checks rather than continuous traffic generation.

Flexible deployment : can be run on multiple hosts, fetch socket lists from a public API, and send results to various notification channels (Telegram, Pushgateway, plain text).

Technical Principles

Dish simulates a client connection to the target endpoint. For TCP it performs the three‑way handshake; for UDP it sends a single packet and waits for a response. The tool parses the network response to classify the outcome as SUCCESS, REFUSED, TIMEOUT, or RST. An optional state‑machine model tracks intermediate states such as SYN_SENT, FIN_WAIT, and TIME_WAIT. Configurable timeout and retry parameters reduce false negatives while keeping overhead low.

Typical Use Cases

Service availability monitoring – replaces telnet or nc for batch port checks.

Fault isolation – quickly identify network interruptions, service crashes, or firewall rule misconfigurations.

Automated operations – integrate into CI/CD pipelines as a post‑deployment health check.

Installation & Usage

Dish can be installed via the Go toolchain or Homebrew:

go install go.vxn.dev/dish/cmd/dish@latest

brew install dish

Run Dish with a local JSON file that lists sockets to test: dish /opt/dish/sockets.json Or provide a remote API endpoint that returns the same JSON structure:

dish http://restapi.example.com/dish/sockets/:instance

Common flags (selected examples): -timeout uint: connection timeout in seconds (default 10). -cache: cache the remote socket list. -cacheDir string: directory for cached data (default “.cache”). -cacheTTL uint: cache validity in minutes (default 10). -target string: URL or path to push results (e.g., Pushgateway endpoint). -telegramBotToken string and -telegramChatID string: send a notification via Telegram. -verbose: enable console logging.

General syntax: dish [FLAGS] SOURCE Example – check TCP port 80 on example.com:

dish --host example.com --port 80 --protocol tcp

Example – UDP DNS query with a 2‑second timeout:

dish --host 8.8.8.8 --port 53 --protocol udp --timeout 2

Limitations

No built‑in historical data storage; long‑term trend analysis requires external systems such as Prometheus + Grafana.

Only checks transport‑layer connectivity; it does not perform HTTPS or other application‑layer validation.

Conclusion

Dish provides a focused, low‑overhead solution for diagnosing socket connectivity issues. Its strength lies in fast, precise detection of reachable, refused, timed‑out, or half‑open connections. For comprehensive observability, combine Dish with a time‑series database or monitoring stack.

Repository: https://github.com/thevxn/dish