Cyber Shield: A Practical Cyber Security Project

This is a simulated cybersecurity project built in Cisco Packet Tracer. It demonstrates network segmentation, threat detection, logging, access control, and incident response using a multilayer switch and multiple VLANs.

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🧠 Objective

To implement core cybersecurity concepts in a simulated enterprise network environment using practical tools such as VLAN segmentation, ACLs, port security, DHCP snooping, ARP inspection, syslog, and simulated attacks.

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🖥️ Topology Overview

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🧩 Network Structure

• Multilayer Switch (MLS) used for Inter-VLAN Routing
• Switch0–Switch3 for VLAN distribution
• 4 VLANs:
  • VLAN 10: Management
  • VLAN 20: HR
  • VLAN 30: Finance
  • VLAN 40: Guests
• VLAN 99: Isolated attacker network

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🔒 Security Implementations

1. Network Security

• VLAN Segmentation
• Port Security (restrict MACs on ports)
• DHCP Snooping (on Switch1 and Switch0)
• Dynamic ARP Inspection (on Switch0)
• Access Control List (ACL) to block attacker (BLOCK_ATTACKER)

2. Threat Simulation

• Attacker in VLAN 99 assigned static IP
• Spoofing attempt simulated and blocked

3. Logging & Monitoring

• Syslog Server receives security logs
• NTP used for time synchronization

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🔄 Failover and Testing

• Tested attacker’s ability to reach sensitive VLANs
• Verified ACL functionality using ping tests
• Verified blocking via DHCP Snooping & ARP Inspection
• show log, show ip dhcp snooping binding, show mac address-table used for validation

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⚙️ Configuration Highlights

Access Control List:

ip access-list extended BLOCK_ATTACKER
 deny ip 192.168.99.10 0.0.0.0 any
 permit ip any any

DHCP Snooping:

ip dhcp snooping
ip dhcp snooping vlan 10,20,30,40,99
int fa0/5
 ip dhcp snooping trust

DAI:

ip arp inspection vlan 99
int fa0/4
 ip arp inspection trust

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🧪 Verification Commands

show vlan brief
show ip interface brief
show running-config
show mac address-table
show ip dhcp snooping binding
show ip arp inspection
show log

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📁 Files Included

• CyberShield.pkt: Main Packet Tracer file
• README.md: This documentation file
• topology.png: Network topology image

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✅ Conclusion

This simulation offers a full-stack view of how security can be layered in an enterprise network. From segmentation and ACLs to logging and spoofing defense, it serves as a strong foundational project for entry-level network security learning and demonstration.