Network 101
Purpose
Configure and test common network services (HTTP, HTTPS, SNMP, SMB) for penetration testing lab environments. Enable hands-on practice with service enumeration, log analysis, and security testing against properly configured target systems.
Inputs/Prerequisites
- Windows Server or Linux system for hosting services
- Kali Linux or similar for testing
- Administrative access to target system
- Basic networking knowledge (IP addressing, ports)
- Firewall access for port configuration
Outputs/Deliverables
- Configured HTTP/HTTPS web server
- SNMP service with accessible communities
- SMB file shares with various permission levels
- Captured logs for analysis
- Documented enumeration results
Core Workflow
1. Configure HTTP Server (Port 80)
Set up a basic HTTP web server for testing:
Windows IIS Setup:
- Open IIS Manager (Internet Information Services)
- Right-click Sites → Add Website
- Configure site name and physical path
- Bind to IP address and port 80
Linux Apache Setup:
bash# Install Apache sudo apt update && sudo apt install apache2 # Start service sudo systemctl start apache2 sudo systemctl enable apache2 # Create test page echo "<html><body><h1>Test Page</h1></body></html>" | sudo tee /var/www/html/index.html # Verify service curl http://localhost
Configure Firewall for HTTP:
bash# Linux (UFW) sudo ufw allow 80/tcp # Windows PowerShell New-NetFirewallRule -DisplayName "HTTP" -Direction Inbound -Protocol TCP -LocalPort 80 -Action Allow
2. Configure HTTPS Server (Port 443)
Set up secure HTTPS with SSL/TLS:
Generate Self-Signed Certificate:
bash# Linux - Generate certificate sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 \ -keyout /etc/ssl/private/apache-selfsigned.key \ -out /etc/ssl/certs/apache-selfsigned.crt # Enable SSL module sudo a2enmod ssl sudo systemctl restart apache2
Configure Apache for HTTPS:
bash# Edit SSL virtual host sudo nano /etc/apache2/sites-available/default-ssl.conf # Enable site sudo a2ensite default-ssl sudo systemctl reload apache2
Verify HTTPS Setup:
bash# Check port 443 is open nmap -p 443 192.168.1.1 # Test SSL connection openssl s_client -connect 192.168.1.1:443 # Check certificate curl -kv https://192.168.1.1
3. Configure SNMP Service (Port 161)
Set up SNMP for enumeration practice:
Linux SNMP Setup:
bash# Install SNMP daemon sudo apt install snmpd snmp # Configure community strings sudo nano /etc/snmp/snmpd.conf # Add these lines: # rocommunity public # rwcommunity private # Restart service sudo systemctl restart snmpd
Windows SNMP Setup:
- Open Server Manager → Add Features
- Select SNMP Service
- Configure community strings in Services → SNMP Service → Properties
SNMP Enumeration Commands:
bash# Basic SNMP walk snmpwalk -c public -v1 192.168.1.1 # Enumerate system info snmpwalk -c public -v1 192.168.1.1 1.3.6.1.2.1.1 # Get running processes snmpwalk -c public -v1 192.168.1.1 1.3.6.1.2.1.25.4.2.1.2 # SNMP check tool snmp-check 192.168.1.1 -c public # Brute force community strings onesixtyone -c /usr/share/seclists/Discovery/SNMP/common-snmp-community-strings.txt 192.168.1.1
4. Configure SMB Service (Port 445)
Set up SMB file shares for enumeration:
Windows SMB Share:
- Create folder to share
- Right-click → Properties → Sharing → Advanced Sharing
- Enable sharing and set permissions
- Configure NTFS permissions
Linux Samba Setup:
bash# Install Samba sudo apt install samba # Create share directory sudo mkdir -p /srv/samba/share sudo chmod 777 /srv/samba/share # Configure Samba sudo nano /etc/samba/smb.conf # Add share: # [public] # path = /srv/samba/share # browsable = yes # guest ok = yes # read only = no # Restart service sudo systemctl restart smbd
SMB Enumeration Commands:
bash# List shares anonymously smbclient -L //192.168.1.1 -N # Connect to share smbclient //192.168.1.1/share -N # Enumerate with smbmap smbmap -H 192.168.1.1 # Full enumeration enum4linux -a 192.168.1.1 # Check for vulnerabilities nmap --script smb-vuln* 192.168.1.1
5. Analyze Service Logs
Review logs for security analysis:
HTTP/HTTPS Logs:
bash# Apache access log sudo tail -f /var/log/apache2/access.log # Apache error log sudo tail -f /var/log/apache2/error.log # Windows IIS logs # Location: C:\inetpub\logs\LogFiles\W3SVC1\
Parse Log for Credentials:
bash# Search for POST requests grep "POST" /var/log/apache2/access.log # Extract user agents awk '{print $12}' /var/log/apache2/access.log | sort | uniq -c
Quick Reference
Essential Ports
| Service | Port | Protocol |
|---|---|---|
| HTTP | 80 | TCP |
| HTTPS | 443 | TCP |
| SNMP | 161 | UDP |
| SMB | 445 | TCP |
| NetBIOS | 137-139 | TCP/UDP |
Service Verification Commands
bash# Check HTTP curl -I http://target # Check HTTPS curl -kI https://target # Check SNMP snmpwalk -c public -v1 target # Check SMB smbclient -L //target -N
Common Enumeration Tools
| Tool | Purpose |
|---|---|
| nmap | Port scanning and scripts |
| nikto | Web vulnerability scanning |
| snmpwalk | SNMP enumeration |
| enum4linux | SMB/NetBIOS enumeration |
| smbclient | SMB connection |
| gobuster | Directory brute forcing |
Constraints
- Self-signed certificates trigger browser warnings
- SNMP v1/v2c communities transmit in cleartext
- Anonymous SMB access is often disabled by default
- Firewall rules must allow inbound connections
- Lab environments should be isolated from production
Examples
Example 1: Complete HTTP Lab Setup
bash# Install and configure sudo apt install apache2 sudo systemctl start apache2 # Create login page cat << 'EOF' | sudo tee /var/www/html/login.html <html> <body> <form method="POST" action="login.php"> Username: <input type="text" name="user"><br> Password: <input type="password" name="pass"><br> <input type="submit" value="Login"> </form> </body> </html> EOF # Allow through firewall sudo ufw allow 80/tcp
Example 2: SNMP Testing Setup
bash# Quick SNMP configuration sudo apt install snmpd echo "rocommunity public" | sudo tee -a /etc/snmp/snmpd.conf sudo systemctl restart snmpd # Test enumeration snmpwalk -c public -v1 localhost
Example 3: SMB Anonymous Access
bash# Configure anonymous share sudo apt install samba sudo mkdir /srv/samba/anonymous sudo chmod 777 /srv/samba/anonymous # Test access smbclient //localhost/anonymous -N
Troubleshooting
| Issue | Solution |
|---|---|
| Port not accessible | Check firewall rules (ufw, iptables, Windows Firewall) |
| Service not starting | Check logs with journalctl -u service-name |
| SNMP timeout | Verify UDP 161 is open, check community string |
| SMB access denied | Verify share permissions and user credentials |
| HTTPS certificate error | Accept self-signed cert or add to trusted store |
| Cannot connect remotely | Bind service to 0.0.0.0 instead of localhost |
