Download Network Port Scanner
Glynis Shrake
Find open ports and running services (incl. versions), and do OS fingerprinting in a single TCP port check. Inspect Top 100 TCP ports for free or get a paid plan to automate and schedule extensive custom scans for even more ports.
Each Nmap port scan against a target IP address or hostname automatically maps the attack surface and gives accurate data for your reconnaissance work. Sign up for a paid account to perform deep port scanning with additional options.
For even more effective port scanning, our tool supports scheduled and parallel scans (with notifications), automated Nmap scans with scan templates and pentest robots, and automatic attack surface mapping.
Each port check produces a professional report you can share with clients, managers, and other decision-makers. We also keep our port scan tool up to date through constant improvements in functionality, performance, and integration with the other platform tools and features.
Your browser doesn't support HTML5 video. Here is a link to the video showing how the Network Vulnerability Scanner displays findings in a report generated while scanning for a random target instead.
Malicious hackers also rely on public port scanners to discover exposed and outdated network services they can exploit to gain unauthorized access to a target. This is why offensive security pros need reliable port scanning tools to keep ahead of remote attackers and proactively reduce risk.
The main benefit of using an online version of the Nmap port scanner (vs using it on your local machine) is that it gives you an external view of your systems as any malicious hacker from the Internet has. If you do the same scan from your internal network you may obtain different results because of various firewalls and network restrictions. Furthermore, our port scanner is:
The scanner allows you to easily map the network perimeter of a company, check firewall rules and verify if your services are reachable from the Internet. Based on Nmap Online, it performs accurate port discovery and service detection.
The TCP Port Scanner in our cloud platform gives you two options: either approach your target as an external attacker would or do port scans directly against your services, as if the firewall has already been bypassed. The resulting Nmap scan report gives you the chance to identify and fix the root causes of security risks your target presents.
The scanner attempts to check if the target host is live before probing for open ports. This is essential for optimizing the scan duration when running the online IP scanner against a large range of IP addresses. It would be a waste of time to probe for open ports on a 'dead' host (e.g. there is no server at a given IP).
This is the default scanning method, also enabled in our online open port scanner. Nmap does a half-open TCP connection, knowing the port is open as soon as the server responds with SYN-ACK. The sequence of packets in this case is: SYN, SYN-ACK, RST.
Once Nmap finds a list of ports, it can do a more in-depth check to determine the exact type of service running on that port, including its version. This is necessary because common services can run on non-standard ports (e.g. a web server running on port 32566). Service detection is enabled with the -sV parameter.
After you check website open ports or do an IP port scan, you can act on the findings right from the list of results. A handy drop-down gives you the option to further scan open ports with various tools such as our Website Scanner, Network Vulnerability Scanner, URL Fuzzer, and Website Recon (for either URLs or IPs).
The arsenal of reconnaissance tools on our cloud platform also includes dedicated scanners that help you Find Domains, Find Subdomains, Find Virtual Hosts, find juicy information with Google Hacking, and perform a thorough UDP Port Scan.
For instance, this Recon Robot discovers all subdomains of a target domain and does deep port scanning and service discovery. For each web port, it does recon to gather technologies and take screenshots and delivers all the data aggregated in the unified Attack Surface view.
With your TCP port scan report, you can start digging deeper and pursue the most interesting findings in it while also getting inspiration for the next stages in your engagement, particularly around security issues related to business logic.
Network ports are the communication endpoints for a machine that is connected to the Internet. When a service listens on a port, it can receive data from a client application, process it, and communicate a response.
Port scanning is part of the first phase of a penetration test (reconnaissance) and allows you to find all network entry points available on a target system. Port scan techniques are different for TCP and UDP ports, which is why we have dedicated tools for each one.
The advanced port scanner tool, which is essentially an open port checker, will provide you with information regarding valid methods of connecting to a network. Scan your network for open ports with this free port scanner tool and determine if those open ports need to be closed to provide more network security and less vulnerabilities.
A port, referred to as a server port or Internet port, is a virtual point of network connection. Network ports are used for routing incoming information from a network to specific applications to a designated machine. They are software-based, each uniquely associated with a specific process or service. Therefore, computers are able to distinguish between different kinds of traffic.
Ports are all assigned a number and standardized across all network devices. There is an IP range for available IP addresses; similarly, between the User Datagram Protocol (UDP) ports and Transmission Control Protocol (TCP) ports, there are 65,536 ports open for communication. However, lower-number ports are most often used.
In many cases, port numbers are reserved for specific protocols across all routers. For example, port 25 is reserved for SMTP (Simple Mail Transfer Protocol) across networks. Subsequently, this standardizes ports and port forwarding for all users.
Also referred to as an open port scanner or IP port scanner, a port scanner is a free tool that displays which checks open ports on a network and shows which are available for communication. Determining whether or not a port's open can help with setting up IP security cameras. Furthermore, it helps figure out if a network is secure. You can check on other network-related operations and network admin features with a port checker or port scan tool.
Hackers also use port checkers to expose vulnerabilities in a network. For reasons like this, it's important for users to use the port checking tool on their own network to scan for weaknesses and make sure they have a strong firewall established on their device. However, scanning for open ports on your own network with the online open port checker is completely legal.
To begin and scan open ports on an IP, enter a valid IP address or URL at the top of the page. After that, you can scan ports on the IP/URL individually or in pre-made groups. If you are a Gold Member, you can also scan ports in a numeric range or in a custom group (no more than 100 ports at once for any scan type).
If a port is displayed as open, that means it is open for remote communication. Otherwise, the port should be closed to remote communication. However, just because a port displays as closed through our tool doesn't mean that it is closed. You should always double-check your router configuration to be sure. You can also double-check with another port scanner online, like the Nmap port scanner.
Some Internet service providers intentionally block popular ports, like 21 or 80, on residential connections to deter customers from hosting their own FTP servers and websites. By blocking popular ports at the ISP level, they provide a level of security for customers. Slow network speeds or slow machines can also lead to ports incorrectly being classified as closed.
Using the open port checker above to check your ports will also tell you if you have any available ports. If you need access to more tools, the WhatIsMyIP home page provides access to those as well as your IP address and IP details.
Port scanning is the process of analyzing the security of all ports in a network. It involves identifying open ports and also sending data packets to select ports on a host to identify any vulnerabilities in received data.
This is why free open port scanners should only be used by network administrators to determine the level of network visibility available to potential cyber attackers. For maximum security, all free port scanners should be supported with additional security solutions.
When a port is open, data packets are permitted to flow in and out of your local network through that port. When a port is closed, all the traffic specific to that port is blocked, preventing it from entering the local network.
For example, in order to facilitate the connection of remote computers to a business network, port 3389 needs to be open and forwarding to each remote device. Without this port in operation, the remote workforce model that's so essential in the world today would not be possible.
Open ports aren't inherently dangerous. Security risks are introduced by the external services that communicate through them. So if a device or vendor linked to a network port has a poor security posture, that open port becomes dangerous and should be closed or filtered.
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