Port Scanner Tool | What Is a Port Scanner?

The advanced port scanner tool is essentially an open port checker. It will provide you with information regarding valid network connection methods. Scan your network for open ports with this free port scanner tool. It will determine if those open ports need to be closed to provide more network security and fewer vulnerabilities.

What is a port?

A port, also known 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 can distinguish between different kinds of traffic.

Say you wanted to enable remote desktop on a Windows PC within your network. You'd need to ensure port 3389 was open and forwarding to the appropriate computer.

Ports are all assigned a number and standardized across all network devices. There is an IP range for available IP addresses. Similarly, between the UDP ports and TCP ports, there are 65,536 ports open for communication. However, lower-number ports are most often used.

Port numbers are often reserved for specific protocols across all routers. For example, port 25 exists for SMTP (Simple Mail Transfer Protocol) across networks. Subsequently, this standardizes ports and port forwarding for all users.

What is an online port scanner?

A port scanner is a free tool that displays and checks open ports on a network. It shows which are available for communication. Determining whether or not a port is open can help set up devices on a network.

Furthermore, it helps figure out if a network is secure. A port checker or port scan tool can also check other network-related operations and network admin features. This tool is also referred to as an open port scanner or IP port scanner.

Hackers also use port checkers to expose vulnerabilities in a network. For this reason, it's important for users to use the port checking tool on their own network to scan for weaknesses. However, scanning for open ports on your own network with the online open port checker is completely legal.

How does a port scanner work?

As established above, a port scanner is a software tool that identifies open ports on a computer or network. It detects potential security risks and vulnerabilities. It works by sending packets to specific ports on a target system. Then, the tool analyzes the responses to determine which ports are open and what services are running.

First, the scanner identifies the target IP address. Then, the user specifies which ports to scan. Once these are established, the scanner sends packets to the specified ports. The scanner listens for responses from the host.

It responds accordingly, as the responses indicate the status of each port. A port can be labeled as Open, Closed, or Filtered, which means no response was received.

After the responses are received, the results are compiled into a report. Users can assess the reports for their network security.

Why use a port scanner? Uses of port scanners

The port scanner tool is useful for anyone who wants to assess and protect their network. It scans ports, identifying which are open or closed, to help users set up network processes. It can also be used for any of the following tasks.

• Network troubleshooting. The tool helps you identify issues with your own network configuration or troubleshoot connectivity problems.
• Penetration testing. In penetration testing, users simulate a cyberattack to test their system's security. Port scanning is an essential part of this process.
• Vulnerability assessment. The port scanner can determine whether there are any vulnerabilities that currently exist with open ports.

You can use the tool to identify open ports, test network connectivity, and gather useful information.

How do I use the port scanner tool?

To use the port scanner tool, enter your IP or URL in the tool's top bar. Select which individual port or group of ports you'd like to scan. Click Scan and you'll receive results shortly.

You can scan multiple ports simultaneously with the tool. You can also choose to scan a single port if you have security concerns or issues.

Scan types

To begin and scan open ports on an IP, enter a valid IP address or URL at the top of the page. Afterward, you can scan ports on the IP or 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. However, you can include no more than 100 ports at once for any scan type.

• To scan individually, select Individual, input a valid port number, and select Scan. The tool will display the status of the chosen port below the scan button.
• To scan by group type, select Group and choose a group from the drop-down menu. Ports contained in the group will then be displayed below the drop-down menu. After confirming your selection, click Scan. The tool will then display the status of each port in the group below the scan button.
• To scan by numeric range, select Range, input a valid port number to start, input another valid port number to stop, and select Scan. Subsequently, the tool will display each port's status, including the starting and ending ports below the scan button.
• To scan by custom group, select Custom. Enter each desired port to scan on its own line in the text box shown, and select Scan. The tool will then display the status of each inputted port below the scan button.

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 it is closed.

To be sure, you should always double-check your router configuration. You can also double-check with another port scanner online, like the Nmap port scanner.

Some Internet service providers purposely block popular ports on residential connections, like 21 or 80. They do this 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.

How to get your port number

Follow these steps for your computer to get your server's port numbers so you can access different sites and servers online.

To get port numbers on Windows:

1. Start up the command prompt.
2. Type ipconfig.
3. Type netstat -a for a list of all port numbers.

To get port numbers on a Mac:

1. Launch Terminal.
2. Enter the command netstat -an.

You'll see a list of ports returned to you.

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 What Is My IP home page provides access to those, your IP address, and your IP details.

Types of port scanners

There are four main types of port scanners available to users. They're classified based on their deployment, their accessibility, and how available they are.

• Online port scanners are web-based services that let users scan ports from the web. Users don't need to download any additional software, making these scanners ideal for quick checks.
• Offline port scanners are software-based tools that run locally on a user's computer. They provide more customizable scans and don't require an Internet connection. These work best for large network scans or for those who need detailed reports.
• Commercial port scanners are sold by companies as larger security plans. They are updated regularly and work best for large enterprises that need reliable and current software. These types of scanners may also include other security features.
• Open-source port scanners are available for free and developed by a community of users online. They can be modified by anyone, making them ideal for users who need a customizable tool. Nmap is an example of an open-source scanner tool.

All four types of port scanners serve different needs. When choosing a scanner, assess the type of results you need and the size of your network.

Benefits and limitations of port scanners

Like all tools, port scanners have their strengths and their limitations. Before you use the tool, consider the benefits and the potential issues with doing a port scan.

The benefits include:

• Network security enhancement. The tool helps identify open ports, which are potential entry points for cybercriminals. This enhances overall network security.
• Network management. Administrators can use the port scanner tool to check network services. Through this, they make sure that no unnecessary ports remain open.
• Troubleshooting. The tool helps diagnose network issues by mapping out network discrepancies and connectivity problems.

However, the potential issues with the scanner tool are:

• False results. If you have network protections in place, like a firewall, the tool can sometimes give incorrect results.
• Network disruption. Aggressive scanning can slow down or disrupt your network due to the high volume of requests.
• Legal concerns. If you perform a scan without authorization, it can potentially lead to legal issues.

Port scanners are an excellent tool for network security and network management. However, make sure to use them safely and ethically.

Port Scan Groups

Basic Ports

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• 21 - File Transfer Protocol (FTP)
• 22 - Secure Shell (SSH)
• 25 - Simple Mail Transfer Protocol (SMTP)
• 80 - Hypertext Transfer Protocol (HTTP)
• 110 - Post Office Protocol v3 (POP3)
• 143 - Internet Message Access Protocol (IMAP)
• 443 - Hypertext Transfer Protocol over TLS/SSL (HTTPS)
• 445 - Microsoft-DS (Directory Services) Active Directory
• 502 - Modbus Protocol
• 587 - Simple Mail Transfer Protocol (SMTP)
• 993 - Internet Message Access Protocol over TLS/SSL (IMAPS)
• 995 - Post Office Protocol 3 over TLS/SSL (POP3S)
• 2525 - Simple Mail Transfer Protocol (SMTP) Alternate
• 3306 - MySQL Database System
• 3389 - Microsoft Terminal Server (RDP)

Web Ports

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• 23 - Telnet Protocol - Unencrypted Text Communications
• 43 - WHOIS Protocol
• 53 - Domain Name System (DNS)
• 67 - Bootstrap Protocol (BOOTP) Server; also used by Dynamic Host Configuration Protocol (DHCP)
• 68 - Bootstrap Protocol (BOOTP) Server; also used by Dynamic Host Configuration Protocol (DHCP)
• 69 - Trivial File Transfer Protocol (TFTP)
• 123 - Network Time Protocol (NTP)
• 137 - NetBIOS Name Service
• 138 - NetBIOS Datagram Service
• 139 - NetBIOS Session Service
• 161 - Simple Network Management Protocol (SNMP)
• 162 - Simple Network Management Protocol Trap (SNMPTRAP)
• 213 - Internetwork Packet Exchange (IPX)
• 389 - Lightweight Directory Access Protocol (LDAP)
• 636 - Lightweight Directory Access Protocol over TLS/SSL (LDAPS)
• 989 - FTPS Protocol (data), FTP over TLS/SSL
• 990 - FTPS Protocol (control), FTP over TLS/SSL
• 1720 - H.323 call signaling
• 2082 - CPanel Default
• 2083 - CPanel Default SSL
• 2086 - WebHost Manager Default
• 2087 - WebHost Manager Default SSL
• 2095 - CPanel Default Web Mail
• 2096 - CPanel Default SSL Web Mail

Game Ports

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• 433 - Xbox Live and/or Games for Windows Live; Playstation 4/5; Fortnite
• 465 - Playstation 4 Red Dead Redemption 2
• 983 - Playstation 4 Red Dead Redemption 2
• 1725 - Valve Steam Client
• 1935 - Playstation 4/5; Call of Duty: Warzone; Battlefield 2042; Fortnite; Red Dead Redemption 2
• 2302 - ArmA Multiplayer; Halo: Combat Evolved Multiplayer
• 3074 - Xbox Live and/or Games for Windows Live; Halo Infinite; Call of Duty: Warzone; Battlefield 2042; Fortnite; PubG; Forza Horizon 5;  Rocket League; Hunt: Showdown; Grand Theft Auto V; Red Dead Redemption 2
• 3478-3480 - Playstation 4/5; Call of Duty: Warzone; Battlefield 2042; Fortnite; PubG; Rocket League; Hunt: Showdown; Grand Theft Auto V;  Red Dead Redemption 2
• 3478-3480 - Playstation 3; Grand Theft Auto V
• 3479 - Xbox Live and/or Games for Windows Live; Fortnite
• 3659 - Xbox Live and/or Games for Windows Live; Battlefield 2042
• 3724 - World of Warcraft; Club Penguin Disney
• 5060 - Xbox Live and/or Games for Windows Live; Fortnite
• 5062 - Xbox Live and/or Games for Windows Live; Fortnite
• 5222 - Battlefield 2042 Steam Client; Xbox Live and/or Games for Windows Live; Fortnite; Playstation 4/5; Fortnite
• 6112 - Blizzard's Battle.net Gaming Service; ArenaNet Gaming Service; Relic Gaming Service; Club Penguin Disney
• 6250 - Xbox Live and/or Games for Windows Live; Fortnite
• 6667 - Nintendo Switch
• 9988 - Battlefield 2042 Steam Client
• 10070-10080 - Playstation 4 Red Dead Redemption 2
• 12000 - 65000 - Xbox Live and/or Games for Windows Live; Fortnite
• 12035 - Linden Lab Viewer to Sim on SecondLife
• 12400 - Nintendo Switch
• 14000-14016 - Xbox Live and/or Games for Windows Live; Battlefield 2042
• 14567 - Battlefield 1942
• 17502 - Battlefield 2042 Steam Client
• 20000-20100 - Battlefield 2042 Steam Client
• 22990 - Battlefield 2042 Steam Client
• 22990-23006 - Xbox Live and/or Games for Windows Live; Battlefield 2042
• 25200-25300 - Xbox Live and/or Games for Windows Live; Battlefield 2042
• 27014-27050 - Xbox Live and/or Games for Windows Live; Call of Duty: Warzone
• 27015-27030 - Battlefield 2042 Steam Client; Red Dead Redemption 2 Steam Client
• 27015, 27036 - Halo Infinite Steam Client; PubG Steam Client; Forza Horizon 5 Steam Client; Rocket League Steam Client; Hunt: Showdown Steam Client; Grand Theft Auto V Steam Client
• 27036 - Red Dead Redemption 2 Steam Client
• 27037 - Battlefield 2042 Steam Client
• 28910 - Nintendo Switch
• 28960 - Call of Duty; Call of Duty: United Offensive; Call of Duty 2; Call of Duty 4: Modern Warfare; Call of Duty: World at War
• 29900 - Nintendo Switch
• 29901 - Nintendo Switch
• 29920 - Nintendo Switch
• 30211-30217 - Playstation 4 and/or Xbox Live and/or Games for Windows Live and/or Steam Client; Red Dead Redemption 2
• 42127 - Battlefield 2042 Steam Client
• 61088 - Xbox Live and/or Playstation 4 and/or Steam Client; Hunt: Showdown

Malicious Ports

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• 26 - W32.Netsky
• 1080 - W32.Beagle; WinHole; HLLW.Deadhat;  Webus
• 2745 - Bagle Virus Backdoor; Beagle
• 3127 - W32.Mockbot; Solame;  Novarg(Mydoom); W32.HLLW.Deadhat
• 4444 – Napster; Prosiak; Swift Remote; Blaster.Worm;  W32.HLLW.Donk; W32.Mockbot; W32.Reidana
• 5554 - W32.Dabber; Sasser
• 8866 - W32.Beagle
• 9898 – CrashCool; Dabber
• 12345 – Amitis; Ashley; Cron/Crontab; Fat Bitch Trojan; GabanBus; Mypic; NetBus; NetBus Toy; NetBus Worm; Pie Bill Gates; Whack Job; X-bill
• 27374 - Bad Blood; Baste; Ramen; Seeker; SubSeven; Subseven 2.1.4 DefCon 8;  SubSeven Muie; Ttfloader
• 31337 - Back Orifice; Back Orifice 1.20 Patches; Back Orifice Russian; Baron Night; Beeone; BO Client; BO Facil; BO Spy; BO2; Cron/Crontab;  Emcommander; Freak2k; Freak88; c; Sockdmini; W32.HLLW.Gool

Frequently asked questions

What is port scanning in networking?

Port scanning is a technique used to identify open ports available on a network.

How does Nmap work?

Nmap is a network scanning tool that explores devices on a network and decides which ports are available. It determines what services they offer and if any packet filters are in use. Then, it sends packets to those ports and analyzes the responses. Essentially, it maps the network.

What are the types of port scans?

There are several types of port scans, such as:

• TCP Connect scans
• SYN scans
• FIN scans
• NULL scans
• ACK scans

Each of these scans uses different packets or packet variations to serve a unique purpose.

Is port scanning illegal?

No, port scanning is not inherently illegal.