Hub, Switch, Router: The Difference

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In cybersecurity, everything goes through the network. If you don’t know how data flows, you can’t protect it:

  • Hub: Sends everything to everyone → No confidentiality, ideal for sniffing attacks.
  • Switch: Sends data to the correct machine via MAC address → More secure but vulnerable to network attacks (e.g., MAC flooding).
  • Router: Connects multiple networks, applies rules (IP, NAT, VPN) → Filters traffic, isolates segments, and logs connections.

Understanding these devices helps in:

  • Placing security tools (firewalls, IDS/IPS) correctly.
  • Segmenting the network to limit attack spread.
  • Analyzing and controlling traffic during incidents.

You Should Know:

1. Hub Security Risks & Detection

Since hubs broadcast all traffic, they are prime targets for sniffing. Detect sniffers with:

sudo tcpdump -i eth0 -n -c 100

Check for unusual ARP traffic (indicates ARP spoofing):

sudo arpwatch -i eth0

### **2. Switch Security & Mitigation**

Switches use MAC tables, but attackers can flood them:

**Prevent MAC Flooding:**

sudo macof -i eth0 -n 1000 # Simulate MAC flooding (for testing)

**Enable Port Security (Cisco Example):**

switch(config-if)# switchport port-security 
switch(config-if)# switchport port-security maximum 5 
switch(config-if)# switchport port-security violation restrict 

### **3. Router Security & Hardening**

Routers control traffic flow. Secure them with:

**Block ICMP Ping (Linux Router):**

sudo iptables -A INPUT -p icmp --icmp-type echo-request -j DROP

**Enable NAT (IP Masquerading):**

sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

**Log Suspicious Traffic:**

sudo iptables -A INPUT -p tcp --dport 22 -j LOG --log-prefix "SSH Attempt: "

### **4. Network Segmentation (Best Practice)**

Isolate critical systems using VLANs:

**Linux VLAN Setup:**

sudo vconfig add eth0 10 # Create VLAN 10 
sudo ifconfig eth0.10 up 

**Windows VLAN (PowerShell):**

New-NetLbfoTeam -Name "VLAN-Team" -TeamMembers "Ethernet1","Ethernet2" -TeamingMode SwitchIndependent

## **What Undercode Say:**

Understanding network devices is crucial for cybersecurity. Hubs are obsolete due to security flaws, while switches and routers form the backbone of secure networks. Always:
Monitor ARP & MAC tables for anomalies.
Segment networks to limit breach impact.
Log & filter traffic at routers.
Disable unused ports on switches.

For deeper security:

  • Use SNMP monitoring (snmpwalk -v2c -c public <IP>).
  • Implement 802.1X authentication on switches.
  • Regularly audit firewall rules (iptables -L -v -n).

## **Expected Output:**

A hardened network with:

  • Switches protected against MAC flooding.
  • Routers filtering malicious traffic.
  • Segmented VLANs isolating critical assets.
  • Logs tracking unauthorized access attempts.

**Further Reading:**

References:

Reported By: Biren Bastien – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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