DNS
TCP Port Checker & Security Scanner
Scan target hostnames or IP addresses to check whether specific TCP service ports (HTTP, HTTPS, SSH, Databases) are open, filtered, or reachable.
How to use
- Enter a domain, URL, or value relevant to TCP Port Checker & Security Scanner.
- Run the check and review the output carefully.
- Apply recommended fixes, then run the check again to verify.
Common use cases
- Pre-deployment validation for TCP Port Checker & Security Scanner.
- Incident triage when security checks fail in production.
- Periodic security review as part of technical SEO and hardening.
Example inputs
validatethis.org1.1.1.1google.comCommon issues and fixes
Connection timed out
A firewall or cloud security group (e.g. AWS SG) is silently dropping SYN packets.
Connection refused
The server is reachable, but no daemon is listening on the requested port.
High-risk port open
Leaving unencrypted ports (FTP 21, Telnet 23) or databases (MySQL 3306, Redis 6379) open to the public internet creates vulnerability to brute force.
Recommended remediation
Close unused ports with ufw / iptables. Place databases behind private VPCs or SSH tunnels rather than exposing them publicly.
FAQ
Is TCP Port Checker & Security Scanner free to use?
Yes. This tool is free and can be used without account registration.
Do you store submitted values?
Only the minimum processing needed for the check. For client-side tools, data stays in your browser.
How should I use these results?
Use the output as a diagnostic baseline, apply fixes in your stack, then re-run the check to confirm remediation.
Related security tools
SSL Checker
Live TLS probe: issuer, expiry, SAN, and certificate chain for any domain. Not SSL Labs.
DNS Lookup
Query DNS records (A, AAAA, MX, TXT, NS, CNAME) for any domain using public DNS API.
Uptime Checker
Quick one-off URL check. HTTP status + response time.
Reverse DNS (PTR) Lookup
Look up PTR hostname for an IP. Reverse DNS for IPv4/IPv6. Like HackerTarget.
Run a full security check
After this tool passes, run related header and policy checks to catch transport and browser-level risks.