Kiểm tra port mở
Kiểm tra port TCP public có thông tới app server không — hữu ích khi cài đặt SSH, HTTP, custom port.
AK
appkiro.comCheck whether selected TCP ports are reachable on a public IP address or domain.
Common ports
Online Port Checker tests whether this app server can open a TCP connection to the ports you enter. It is useful for quick public-facing checks: web servers, mail submission ports, SSH exposure, database ports that should not be public, and firewall rules after a deployment.
Use a public domain or public IP address. Localhost, private IP ranges, and internal-only hosts are blocked, because this tool is meant for public network checks.
You can type ports separated by commas or spaces, or use the common ports shortcut. The checker limits the number of ports per run, so it is better for targeted troubleshooting than broad scanning.
An open result means the TCP handshake was accepted. It does not prove login works, TLS is configured correctly, or the application behind the port is behaving. For SMTP and FTP, use the dedicated tools below because they perform protocol-level checks.
CLI equivalent
nc -vz example.com 80, 443Network checks run from the app server, so results reflect what is reachable from that public environment. Localhost, private IPs, and internal-only targets are blocked.
The check runs from the app server, so private and localhost targets are blocked to avoid probing internal infrastructure.
No. It only means a TCP connection was accepted. The protocol, login, certificate, or application can still fail.
Your office, VPN, or hosting network may have access that the public internet does not. Firewalls can allow one source and block another.
Only a limited number per run. This tool is for quick checks, not full security scanning.