Port scanners and port checker tools are the most essential parts of finding the open ports and the status of the port.
The open ports mean a TCP or UDP port number that is arranged to acknowledge packets.
Web pages or FTP services require their particular ports to be “open” on the server so as to be freely reachable.
What is the Open Port Scanner?
An open port scanner is a tool that is used to check the external IP address and identify open ports on the connection.
It is used to detect whether the port forwarding is set up accurately or whether the server applications are being blocked by a firewall.
Port Checker tools are used to examine the network for ports that are commonly forwarded.
Few ports, such as port 25, are usually blocked at the ISP level trying to intercept suspicious tasks.
Each data contains a port number, which allows the protocols to determine their desired location and redirect them accordingly.
Most Used Ports
20 FTP – Data
21 FTP – Control
22 SSH Remote Login Protocol
23 Telnet
25 Simple Mail Transfer Protocol (SMTP)
110 POP3
115 Simple File Transfer Protocol (SFTP)
118 SQL Services
53 Domain Name System (DNS)
443 HTTPS
143 IMAP
389 LDAP
37 Time Protocol
123 Network Time Protocol
530 Remote procedure call
547 DHCPv6 server
Time needed: 5 minutes.
How to Scan Open Ports in Windows?
- Press the Windows key and run key at the same time to open the command prompt.
- Type cmd and hit enter.
- In the command prompt type “netstat -a” and hit enter.
- In a few seconds, it displays a complete list of ports that establish the connection.
Best Port Checker & Port Scanner Tools
- Advanced Port Scanner
- TCP Port Scan with Nmap
- IPVOID
- Network Port Scanner Tool
- DNS Tools
- Web Proxy and Privacy Tool
- Solar winds Port Scanner
- IP Tool
- UltraTools
- Yougetsignal
This Open port scanner is the fastest, easy to access, and freely available everywhere.
It helps to find out the open ports on network computers and extract the kind of programs that are running on detected ports.
These programs have an adaptable interface and usable functionality.
Key Features
- Fast port scanning
- Remote access
- Getting information on network devices
- Wake-On-LAN
- Easy access
- Run commands on the remote computer
This Open Port Scanner tool helps to identify which TCP port is open on your target machine and also provides OS information, service information, and also traceroute.
The Nmap Port scanner tool is a web interface for the widely known Nmap port scanner which is implemented with the correct parameter so as to give speed and accuracy.
The scanning process is sending packets to each port and listening for acknowledgment.
This is called an ‘SYN scan’, which sends TCP SYN packets to each port. If a port replies with SYN-ACK, it is flagged as open and an RST is sent back by the Nmap port scanner.
In this way, no full TCP connection is established with the target machine.
Key Features
- Port Scanning
- Custom scanning options
- Able to discover network devices
IPVOID helps to identify services that are running on the server and view TCP open ports.
It also checks and verifies whether the firewall is working accurately. There are security services that block IPs that you don’t hold, so try not to check.
The online tool offers a wide range of scanning options to discover details about IP addresses.
Key Features
- Base64 to Image
- IPv4 CIDR Checker
- DiG DNS Lookup
- IP Geolocation
- Multi URL Opener
This Open port scanner tool helps to check services that are available and running on the server.
If we want to check what OS version is running, and whether ports are open on a server, and whether the server has enabled a firewall or not, then, in this case, to check all the above information, it uses raw IP packets.
This tool is extremely useful to find out if your port forwarding is set up correctly or if your server applications are blocked or not by a firewall.
Key Features
- Port scanning
- Firewall Detection
- IP Finder
- Open Port detection
It helps you to identify which service is accessible outside of the intranet. Machines use a router with NAT to bind with the internet can’t be obtained outside of the intranet.
Although, by using port forwarding, ports can deviate from the router to the particular machine.
This Open port scanner online allows for verifying whether redirection works correctly or not.
Key Features
- Round-trip SMTP monitoring.
- Inbound and outbound email tests and header analysis.
- Performance metrics and historical statistics.
- Configurable real-time alerts.
- Customizable timeouts.
This Open port scanner online tool is also known as “ HideMy[.]name “. If anyone wants to hide their identity and access anything and everything, go for a Web proxy.
This tool hides and changes your IP address, and location and you will stay incognito while using the browser.
It is a median to the machine and required website. You can also watch blocked content and play online games as well.
You can surf the internet with maximum speed and connection. It gives protection, privacy, and liberty on any device while browsing.
Key Features
- VPN Service
- Hide Network Activity
- Protect Passwords
- Unrestricted Internet Access
It scan’s all the IP addresses and TCP and UDP ports to check network vulnerabilities.
You can run the scan from the command line as well, save scan configurations also, and minimize run time scan with multi-threading. Trace end-user and terminal machine connection activity.
It recognizes unknown vulnerabilities and network protocols.
Key Features
- Automated network discovery
- Real-time monitoring and alerting
- Powerful diagnostic capabilities
- Enhanced network security
IP tool is known as “whatismyip[.]com “ Port scanner.
This tool scans the network for open ports and decided if those open ports need to be closed to allow network security and fewer vulnerability.
This Open port scanner tool shows which ports are open for communication on a network. If in case, a port is opened, it is for remote communication.
Key Features
- IP Address Scanner
- IP Address Tracker
- Infoblox DNS and DHCP Monitoring
- IP Address Discovery
With Ultra tools you can check the DNS performance and the DNS records specified to the domain or the hostname.
DNS Traversal Tool gives you more information on whether the DNS servers have propagated to all Nameservers.
It is a cloud-based authoritative DNS service that securely delivers fast and accurate query responses to websites and other vital online assets.
Key Features
- SiteBacker — Monitoring & Failover
- Traffic Controller
- Directional DNS
- DNS Shield
Yougetsignal is the open port checker tool that let you check any external IP address for open ports.
It is a useful tool to check for the restriction placed in the Firewall. With this tool, you can check for all TCP and UDP ports.
With the listed above port scanner tools, you can determine the open ports in the network infrastructure.
It is always recommended to close the ports if they are not in use for security reasons.
Key Features
- Port Forwarding Tester
- What Is My IP Address
- Network Location Tool
- Visual Trace Route Tool
Conclusion
Listed are some of the free tools available online to check for the open ports on the server and for other DNS queries.
We have categorized some of the best port scanner and port checker tools to help to find the open ports and other port-related operations while performing a penetration test on the network.
Most of the suspicious software behaves like a service waiting for connections from a remote assailant so as to give him data or authority over the machine.
The most common security practice is to close unused ports in private machines, in order to block known access to any service which may keep running on the PC without the client’s information, regardless of authorized service is being misconfigured or because of the suspicious software.
Port scanning itself is not illegal, but scanning the destination host without authorization is illegal and you will get into trouble.
TCP Port scanners help the server administrators and penetration testers to examine at which ports the data is entering into the network and to protect it from invaders.
Source: gbhackers.com
