Scan a domain or IP for common TCP ports including 21, 22, 25, 53, 80, 443, 3306, 3389, 5432 and 8080. View open or closed status and latency.
An online port scanner checks whether selected TCP connection points on a domain or IP address accept a connection from the scanner's server. This Port Scanner resolves a supplied hostname, tests a fixed list of common TCP ports, and reports each one as Open or Closed with a small latency value. It also shows the resolved IP address and the number of open ports found.
This is a focused public port check, not a full network security audit. The page does not accept a custom port list, scan a port range, perform UDP checks, identify software versions, or prove that a service is secure. Use it for a quick external connectivity check on a host you own or are explicitly authorised to test, then confirm important findings in the server, firewall, router, or hosting configuration.
The test represents the view from the scanner's hosting environment, not necessarily the view from your laptop or an internal server. A port can be reachable on a private LAN while blocked on the public interface, or open externally while an internal client is routed through a different firewall path. This outside-in perspective is particularly useful for checking public websites, VPS services, router forwarding, and approved remote access rules.
Enter a domain name or IP address and select Scan Ports. When a hostname is supplied, the tool resolves it to an IPv4 address before attempting the checks. A path or web protocol is removed from the input, so the scan is directed at the host rather than at a particular webpage. The result lists the target, resolved IP, each tested port, its familiar service label, Open or Closed status, and the measured connection-attempt time.
The current scanner tests ten predefined TCP ports: 21, 22, 25, 53, 80, 443, 3306, 3389, 5432, and 8080. It makes a short connection attempt to each port and stops after the result is known or the timeout is reached. Because the list is fixed, a service running on another port will not appear in this result. A host may therefore have more listening services than this page reports.
An Open result means the scanner was able to establish a TCP socket to that port from its server. In practical terms, a service or network endpoint accepted the connection. A Closed result means the connection attempt did not succeed within the short test window. The page uses a two-state display, so a failed attempt can also be caused by a firewall silently dropping traffic, a NAT rule, a routing problem, an unavailable host, or a service that is slower than the timeout.
For that reason, Closed does not always mean that no process is listening, and Open does not identify the exact application behind the port. The result describes reachability from this scanner's network at that moment. A local firewall, cloud security group, home router, ISP filter, or corporate egress policy can make the observation different from a test performed inside the same network. Repeat an important check after a configuration change and compare it with the system logs.
Port 21 is commonly associated with FTP, 22 with SSH, 25 with SMTP mail transfer, and 53 with DNS service traffic. Port 80 is the usual HTTP endpoint and 443 is the usual HTTPS endpoint. Port 3306 is commonly used by MySQL, 3389 by Remote Desktop Protocol, 5432 by PostgreSQL, and 8080 is often used for an alternate HTTP service. These labels describe conventional assignments; a service can be configured on a different port.
Ports 110 and 143 are also familiar email ports for POP3 and IMAP, but they are not included in this page's fixed scan list. The same applies to any custom port or port range. An open web port is often expected on a public website, while an exposed SSH, RDP, MySQL, or PostgreSQL port deserves a closer configuration review. An open port is not automatically unsafe, and a closed port is not proof that a host has no security issue; context, authentication, encryption, and access controls still matter.
A port checker can help after enabling port forwarding, moving a website, changing a firewall rule, deploying a mail service, or making a database available to an approved remote application. Scan the exact public hostname or IP, note the resolved address, and compare the result with the intended service. If port 443 is closed after a certificate or web-server change, check the listener and firewall rule. If 3306 or 5432 is open unexpectedly, verify whether public exposure was intentional and restrict it when it is not required.
The latency value is the approximate time for the connection attempt, not a complete performance benchmark. It does not measure page speed, bandwidth, database response time, or the quality of an application session. A slow value can reflect network distance, a firewall timeout, or temporary congestion. For a meaningful diagnosis, combine the online result with local listening-port output, firewall logs, cloud security-group rules, router forwarding settings, and an authorised test from the intended client network.
A website port scanner can report Closed when the domain resolves to a CDN edge, load balancer, or different address than the origin server you expected. IPv4-only hostname resolution, split DNS, NAT, rate limits, and upstream filtering can also change what an external probe sees. The scan does not send application credentials, read files, exploit a service, or perform banner and version detection. It only checks whether a short TCP connection can be made to the predefined ports.
Only scan systems you own or have clear permission to assess. Port checking creates network traffic and may trigger monitoring or abuse controls even when the request is harmless. If an expected port is Open, identify the listening service on the authorised host and apply least-privilege firewall rules. If an expected port is Closed, confirm the service bind address, public DNS, NAT, and firewall path before changing anything. These checks turn a quick online port scan into a responsible troubleshooting step instead of an unsupported security conclusion.