Advanced Port Checker
Check open ports with proxy/Cloudflare bypass capability and detailed network analysis
Port Scanner
Check port status & network connectivity
Ports: 80 (HTTP), 443 (HTTPS), 22 (SSH), 21 (FTP)
Introduction: Ports as Doors of Network Communication
In a network of computers, ports are the doors that open communication between devices from different networks. Like doors in a building, each port gives access to the services and applications that may be used, for example, web browsing, email, file transfers, and remote access.
When these digital doors are not correctly set up, blocked or are not working, it may happen that the services that you really need are out of reach, thus business operations can come to a standstill, and users may get annoyed with not being able to access the services.
Webstatus247's Port Checker
Our comprehensive port scanning tool is at your service in verifying service availability, resolving connectivity troubles, and security configurations check across your network infrastructure. We, in this detailed guide, will talk about everything, from port fundamentals to advanced network diagnostics, which will be a great source of knowledge for you to be able to keep the network at optimal performance and security levels.
Accurate Firewall, Router & NAT Troubleshooting
A port checker instantly verifies whether your firewall rules, NAT configurations, or port-forwarding settings are applied correctly. This helps you quickly catch misconfigurations in routers, cloud firewalls, and security groups.
Real-Time External Service Reachability
It simulates a real external connection, confirming that your app, API, or server is actually accessible from outside your network. This is essential for production systems, remote connection setups, and public-facing services.
What Are Network Ports? The Foundation of Digital Communication
Understanding Ports and Their Purpose
In networking a port is a virtual communication endpoint in the operating system. Whereas an IP address is used to identify a single device on the network, ports are used to identify the different applications or services that are running on the device. This method allows multiple services to be executed on one IP address without any conflicts.
16-bit Numbers
Range between 0 and 65535
Logical Concepts
Virtual, not physical hardware
Standardized Assignments
Common services have standard ports
Protocol Specific
TCP or UDP protocols
The Port Number Hierarchy
Port numbers are categorized into three different ranges:
Used for system services and require administrator privileges to bind
Assigned to specific applications but regular users can use them too
Used mainly for client-side connections and temporary use
How Port Checking Works: The Technology Behind Connectivity Testing
The TCP Handshake Process
Our TCP port checker works by initiating the standard TCP three-way handshake:
SYN Packet
A synchronization packet is sent by the tool to the target port
SYN-ACK Response
The target responds with synchronization acknowledgment if the port is open
ACK Packet
Our tool sends the final acknowledgment to complete the handshake
Connection Established
Successful handshake indicates the port is open and ready for connections
UDP Port Checking Challenges
Checking UDP ports is more challenging due to UDP being a connectionless protocol without handshakes. Our tool implements several techniques:
Service-Specific Probes
Query known UDP services and await their response
ICMP Error Handling
Detect ICMP error messages to determine closed ports
Time-Based Logic
Use timeout periods when no response is received
Protocol-Specific Payloads
Send tailored payloads to elicit replies from services
Common Network Ports and Their Services
Knowing what ports are usually assigned to is essential for network management and troubleshooting.
Essential Well-Known Ports
| Port Number | Service | Protocol | Purpose |
|---|---|---|---|
20/21 | FTP | TCP | File Transfer Protocol (data/control) |
22 | SSH | TCP | Secure Shell remote access |
23 | Telnet | TCP | Unencrypted remote terminal |
25 | SMTP | TCP | Simple Mail Transfer Protocol |
53 | DNS | TCP/UDP | Domain Name System |
80 | HTTP | TCP | Web server (unencrypted) |
110 | POP3 | TCP | Post Office Protocol email |
123 | NTP | UDP | Network Time Protocol |
143 | IMAP | TCP | Internet Message Access Protocol |
443 | HTTPS | TCP | Secure web server (SSL/TLS) |
465 | SMTPS | TCP | SMTP over SSL |
587 | SMTP Submission | TCP | Mail submission with authentication |
993 | IMAPS | TCP | IMAP over SSL |
995 | POP3S | TCP | POP3 over SSL |
1433 | MSSQL | TCP | Microsoft SQL Server |
3306 | MySQL | TCP | MySQL database |
3389 | RDP | TCP | Remote Desktop Protocol |
5432 | PostgreSQL | TCP | PostgreSQL database |
Gaming and Application Ports
Popular software and games use specific ports that can be verified with our port checker:
Minecraft
Minecraft server
Steam/CS:GO
Steam game client and CS:GO
World of Warcraft
World of Warcraft game
Xbox Live
Xbox Live gaming service
TeamSpeak 3
TeamSpeak 3 voice chat
Why Port Checking is Essential for Network Management
Troubleshooting Service Connectivity Issues
Port checking is one of the first diagnostic steps when services become inaccessible:
- Verifying that services are active and listening on expected ports
- Locating firewall blocks preventing legitimate connections
- Detecting incorrectly configured services running on wrong ports
- Diagnosing network routing problems causing port-specific issues
- Confirming port forwarding rules are working as intended
Security Assessment and Hardening
Regular port scanning plays a crucial role in maintaining network security:
- Spotting unauthorized services running on your network
- Locating open ports that should be closed for security reasons
- Checking if security policies are correctly implemented
- Finding potential attack vectors before cybercriminals do
- Complying with various security standards requirements
Network Migration and Configuration Validation
Port checking ensures smooth transitions during network changes:
- Validating new server configurations before going live
- Testing port forwarding rules during router changes
- Verifying VPN connectivity and available ports
- Confirming cloud service configurations are accurate
- Ensuring load balancer port configurations are correct
Detect ISP Restrictions & Network-Level Blocks
Advanced port testing helps identify if your ISP is blocking certain ports (e.g., 25, 445, 135, 21). This saves hours of debugging and helps you determine whether the issue is on your network, your server, or your provider’s side. A port checker reveals unintended open ports that could expose critical services. This helps prevent intrusion attempts, bot attacks, and unauthorized access.
How to Use Webstatus247's Port Checker Tool
Our port checker facilitates straightforward user interfaces for both basic and advanced port scanning.
Navigate to the Tool
Access the Port Checker through Webstatus247's free tools section
Enter Target Information
Input the domain name or IP address of the location you want to check
Specify Ports
Input single port numbers, port ranges, or select from predefined lists
Select Protocol
Choose TCP, UDP, or both based on your requirements
Initiate Scan
Click "Check Ports" to start the scanning process
Analyze Results
Review detailed reports showing port status and response information
Advanced Scanning Options
Our tool offers advanced functionalities for experienced users:
Comprehensive Network Audits
Scan custom port ranges for complete network analysis
Adjustable Scanning Speed
Balance speed and stealth based on your needs
Service Detection
Identify what's running on open ports
Banner Grabbing
Retrieve service information and version details
Interpreting Port Check Results
Understanding different port statuses is essential for proper troubleshooting:
Security Implications of Open Ports
Risk Assessment for Common Open Ports
Open ports can become sources of security risks at different levels:
22/TCP (SSH), 23/TCP (Telnet), 135/TCP (RPC), 445/TCP (SMB)
Frequent targets of exploits and attacks
80/TCP (HTTP), 443/TCP (HTTPS), 3389/TCP (RDP)
Application-dependent risks, frequent brute-force targets
53/UDP (DNS), 123/UDP (NTP)
Essential services but can be misused in attacks
Port Security Best Practices
Implement these measures to keep your port configurations secure:
Least Privilege Principle
Only open absolutely necessary ports
Regular Port Audits
Check open ports monthly using tools like ours
Default Deny Firewall
Block all incoming traffic unless explicitly allowed
Service Hardening
Remove unnecessary services and disable redundant features
Network Segmentation
Place sensitive services in separate network segments
Monitoring and Alerting
Set up alerts for new open ports or changes
Frequently Asked Questions About Port Checking
Is port checking legal?
Checking ports on your own systems is definitely okay. However, if you scan other people's systems, it might be illegal or against terms of service depending on where you are and where the target is. Always have permission before you start probing networks you don't own.
Why do some ports show as "filtered"?
Filtered ports usually mean that a firewall or some network filtering device is stopping port scan packets. In fact, the port could be open; however, you are not allowed to see its status because the firewall is not letting the scanning packets through or is not answering them.
How often should I check my open ports?
Regular port auditing depends on your situation:
- Monthly: For stable production environments
- Weekly: For very dynamic environments with frequent changes
- After any network change: Firewall updates, new services, or infrastructure changes
- Continuous monitoring: For high-security environments
Can port checking damage my network or systems?
Proper port checking will not harm your network or devices. However, aggressive scanning with a high rate of packets may put excessive pressure on vulnerable devices and consume significant bandwidth. Our tool works with safe and conservative parameters by default.
What's the difference between TCP and UDP port checking?
TCP port checking utilizes connection handshakes, providing more reliable port status information. UDP port checking is less reliable because UDP is a connectionless protocol—closed UDP ports often remain silent, making it challenging to distinguish between filtered ports and open ports that simply aren't responding to your probe.
Why can't I access my service even though the port shows open?
Just because a port is open doesn't mean the service is working properly. Possible reasons include:
- The service is running but incorrectly configured
- Authentication or authorization failures
- Application-level errors or crashes
- Lack of resources (memory, disk space)
- Other network-related problems beyond basic port connectivity
Conclusion: Mastering Network Connectivity Through Port Awareness
Network ports are the basic infrastructure that makes all digital communication possible. Understanding the status, configuration, and security of ports is no longer just for network administrators—it's essential for developers, system administrators, security professionals, and anyone responsible for providing reliable digital services.
Webstatus247's Port Checker gives you the visibility needed to manage your network efficiently with minimal effort. By regularly auditing your port settings, proactively solving connectivity issues, and following secure port management practices, you ensure that your network services remain available, performant, and secure.
Don't leave your network connectivity to chance. Include port checking in your regular network maintenance routine and utilize our complimentary tool to keep your network infrastructure healthy, secure, and performing at its best.
🔑 Port Categories
⚡ Quick Tips
- Always get permission before scanning
- Check both TCP and UDP
- Start with common ports first
- Document your findings
- Regularly audit your ports
⏰ Recommended Scan Frequency
- Production: Monthly audits
- Development: Before deployment
- Security: After configuration changes
- Critical: Continuous monitoring
🎮 Common Game Ports
Ready to Master Your Network Security?
Test your port connectivity instantly. Verify service availability, diagnose network issues, and enhance security with our free port checker tool.