Port Range Checker
Scan a small range of TCP ports (up to 64 at a time) on your own server. Built-in limits keep this safe for diagnostics — not for unauthorized scanning.
Quick answer: Scan a small range of TCP ports (up to 64 at a time) on your own server. Built-in limits keep this safe for diagnostics — not for unauthorized scanning.
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Frequently asked questions
- How do I scan a range of ports on my own server?
- Enter your hostname, set From and To (max 64 ports per request), and click Scan. Open ports show in green with their handshake time.
- What's a safe limit for port scanning?
- We cap each request at 64 ports and ~8 scans per 5 minutes. That's enough for diagnosing service issues without looking like an attacker to your firewall.
- Why does a range scan take longer?
- Each port needs its own TCP handshake (or timeout). We run six in parallel, but a 64-port range with timeouts can still take 30+ seconds.
- What's the difference between sequential and parallel checks?
- Sequential probes one port at a time; parallel probes several at once for speed. We use a small parallelism (6) to avoid tripping IDS/IPS systems.
- Why do I get false positives or negatives?
- Stateful firewalls sometimes drop bursts of SYN packets, briefly making open ports look filtered. If a result surprises you, re-run with a smaller range.
- Which ports do SSH, HTTP, HTTPS, and RDP use?
- SSH = 22, HTTP = 80, HTTPS = 443, RDP = 3389 (Windows Remote Desktop). MySQL = 3306, PostgreSQL = 5432, Redis = 6379.
- How do I open ports on my router?
- Log into your router admin page, find the Port Forwarding section, and add a rule pointing the external port to the internal IP and port of the service. Saving the rule usually triggers a reboot.
- What is port forwarding?
- It's a NAT rule that routes inbound connections on a public port to a specific machine on your private LAN. Without it, services on a home network are unreachable from the internet.
- What does "connection refused" mean?
- The host is online but nothing is listening on that port — it sent a TCP RST. Either the service isn't running or it's bound to a different interface.
- How can I export the results?
- Click Export CSV after a scan. The file lists each port with its state, reason, and connection time — handy for tickets and runbooks.