Advanced port scanning and port checking tool for developers, system administrators, and security professionals. Test network connectivity, analyze port status, and perform security assessments - completely free!
Test network connectivity, analyze port status, and perform security assessments with our advanced port scanning and port checking engine.
| Port | Status | Service Detection | Response Time |
|---|
Advanced multi-threaded port scanning and port checking engine delivers results in seconds, not minutes. Optimized for both single port checks and comprehensive range scans.
Intelligent service detection identifies running applications, versions, and potential security vulnerabilities on discovered open ports through our port checker analysis.
Built-in security analysis provides recommendations for hardening your network infrastructure and identifying potential attack vectors - all completely free.
Network ports serve as communication endpoints for various services. Understanding their states is crucial for maintaining secure infrastructure with proper port scanning and port checking:
Actively listening for connections. While necessary for services, each open port represents a potential attack surface that requires monitoring and security hardening.
Not accepting connections but responding to requests. Generally safer but can still provide information to attackers about the target system.
Attackers target vulnerable services running on open ports, exploiting known CVEs or misconfigurations to gain unauthorized access.
Reconnaissance technique where attackers collect service version information to identify specific vulnerabilities.
Once inside a network, attackers use port scanning to discover additional services and expand their foothold.
Modern containerized applications expose numerous ports that require monitoring with port scanners and port checkers for both functionality and security:
| Platform | Port Range | Purpose | Security Notes |
|---|---|---|---|
| Docker | 2375-2376 | REST API (unencrypted/encrypted) | 2375 should never be exposed publicly |
| Kubernetes API | 6443 | Cluster management | Critical - requires strong authentication |
| Kubelet | 10250, 10255 | Node agent communication | 10255 is read-only but deprecated |
| etcd | 2379-2380 | Cluster state storage | Contains sensitive cluster data |
Continuous integration and deployment pipelines introduce new port-based attack surfaces:
Completes the full three-way handshake. More reliable but easily detected by intrusion detection systems. Suitable for authorized port checking.
# Our port checker uses TCP Connect by default
# Advantage: High accuracy
# Disadvantage: Logged by target systems
Sends SYN packets without completing the handshake. Faster and more stealthy but requires raw socket access (not available in web-based port checkers).
# Advanced port scanning technique
# Advantage: Stealthy, fast
# Disadvantage: Requires privileges
UDP port scanning presents unique challenges due to the connectionless nature of the protocol:
# Test specific service connectivity
Test-NetConnection -ComputerName "api.github.com" -Port 443
# Port checker scan for multiple ports with timeout
1..1024 | ForEach-Object {
if(Test-NetConnection -ComputerName "192.168.1.1" -Port $_ -WarningAction SilentlyContinue -InformationLevel Quiet) {
Write-Host "Port $_ is open" -ForegroundColor Green
}
}
# Modern netcat usage for port checking
nc -zv database.example.com 5432
nc -zv 10.0.0.100 3306-3310
# Advanced nmap port scanning
nmap -sS -O api.company.com # OS detection with SYN scan
nmap -sV -p 80,443,8080 web.example.com # Service version detection
# Socket statistics for local port checker services
ss -tulpn | grep :443 # Find what's listening on HTTPS port
# Check local port bindings
sudo lsof -iTCP -sTCP:LISTEN -n -P | grep :8080
# Network connectivity port testing
nc -zv redis.local 6379
telnet mongodb.company.com 27017
# Process-specific port scanner usage
sudo lsof -i :3000 | grep LISTEN
Modern microservices architectures require monitoring of inter-service communication ports with dedicated port scanners and port checkers:
| Database System | Primary Port | Cluster Ports | Monitoring Considerations |
|---|---|---|---|
| PostgreSQL HA | 5432 | 5433-5435 (replicas) | Monitor replication lag via port checker health |
| MySQL Galera | 3306 | 4567, 4568, 4444 | Cluster state synchronization critical |
| MongoDB Replica | 27017 | 27018, 27019 | Primary/secondary election monitoring |
| Redis Cluster | 6379 | 16379 (cluster bus) | Cluster topology changes detection |
Indicates network-level blocking, often by firewalls or security groups. Check routing tables and firewall rules.
Port is closed or no service is listening. Verify service status and port binding configuration.
Intermediate devices are blocking traffic. Common with deep packet inspection firewalls.
Response time analysis helps identify network bottlenecks and service performance issues using port checker data:
Modern security frameworks require continuous verification of network access using port scanners and port checkers:
# Example CI/CD security port scanning integration
# GitHub Actions workflow for port scanner automation
name: Security Port Scanner Check
on: [push, pull_request]
jobs:
security-scan:
runs-on: ubuntu-latest
steps:
- name: Port Checker Security Scan
run: |
nmap -sS --script vuln ${{ secrets.TARGET_HOST }}
# Fail build if high-risk ports detected
Medical device network security requires monitoring with port scanners and port checkers for specialized ports for imaging equipment, patient monitoring systems, and electronic health records.
Payment processing environments require strict port scanner monitoring for compliance with financial regulations and fraud prevention using dedicated port checkers.
Industrial control systems use specialized protocols that require careful port scanner monitoring for operational security with specialized port checkers.