Open Port
Change Detector.
Portwatch scans your servers for open ports, saves a baseline, and alerts you when something changes. New port opened? Service disappeared? You'll know immediately. Scan, diff, alert — on a cron or on demand.
$ portwatch scan --diff
Scanning localhost (1-65535)...
✓ Scan complete — 6 open ports
Port Service State
22 SSH (OpenSSH) open
80 HTTP (nginx) open
443 HTTPS (nginx) open
8080 HTTP (node) NEW ●
3306 MySQL CLOSED ●
6379 Redis open
⚠ 2 changes detected — alerts sent
What It Does
Scan. Diff. Alert.
Portwatch performs TCP port scans against your target hosts, stores the results as a baseline, and compares subsequent scans to detect changes. New ports, closed ports, and service changes are all reported.
TCP Port Scanning
Fast SYN/connect scanning with configurable port ranges. Scan specific ports, common ports, or the full 1-65535 range.
Baseline Diffing
First scan creates a baseline. Every subsequent scan is compared against it. See exactly which ports opened, closed, or changed services.
Change Alerts
Get notified via Slack, Telegram, Discord, or webhook when port changes are detected. Alert includes the full diff with old and new state.
Scheduled Scans
Run as a cron job or systemd timer for continuous monitoring. Portwatch handles the baseline management and diff logic automatically.
Multi-Target
Scan multiple hosts from one config file. Define targets by IP address, hostname, or CIDR range. Each target maintains its own baseline.
Open Source
MIT licensed. Audit the code, contribute, or fork it. Built for transparency and community use.
Configuration
Define targets. Set alerts. Run.
One YAML config for all your targets. Define port ranges, scan intervals, and notification channels.
Alert Format
See what changed. Instantly.
Change alerts include the target, the exact ports that changed, and the before/after state for each.
Install
One command. Scanning in seconds.
The installer downloads the binary, creates a default config, and optionally sets up a systemd timer for scheduled scanning.
Continuous Monitoring
Static snapshots? HostAtlas monitors continuously.
Portwatch gives you periodic scan diffs. HostAtlas gives you continuous port and service monitoring with the agent running on every server — real-time status, alerting, and full infrastructure visibility without manual scanning.