How to Configure VLAN Hopping for Cisco Switches on Attack Prevention

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How to Configure VLAN Hopping for Cisco Switch

• http//www.router-switch.com/

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VLAN Hopping

• VLAN hopping (virtual local area network hopping)
  is a method of attacking a network by sending
  packets to a port that is not normally accessible
  from a given end system.
• The basic concept behind all VLAN hopping attacks
  is for an attacking host on a VLAN to gain access
  to traffic on other VLANs that would normally not
  be accessible. There are two primary methods of
  VLAN hopping switch spoofing and double tagging.
  Following the easy steps to configure VLAN
  Hopping for Cisco Switches on Attack Prevention.

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• Switch-1 (config) vtp mode server
• Switch-1 (config) vtp domain rt
• Switch-1 (config)vtp pruning
• Switch-1 (config)vtp version 2
• Switch-1 (config)vtp password cisco
• Switch-1(config) vlan 99
• Switch-1(config) vlan 10
• Switch-1(config-vlan) name yanfa
• Switch-1(config)interface fastethernet 0/1
• Switch-1(config-if) switchport mode access
• Switch-1(config-if) switchport access vlan 10
• Switch-1(config) vlan 20
• Switch-1(config-vlan) name renshi
• Switch-1(config)interface fastethernet 0/2
• Switch-1(config-if) switchport mode access
• Switch-1(config-if) switchport access vlan 20
• Switch-1(config)interface fastethernet 0/24
• Switch-1(config-if)shutdown
• Switch-1(config-if)switchport trunk
  encapsulation dot1q

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• Switch-2 (config)vtp domain rt
• Switch-2 (config)vtp password cisco
• Switch-2 (config)vtp pruning
• Switch-2 (config)vtp version 2
• Switch-2 (config)vtp mode client
• Switch-2(config)interface fastethernet 0/1
• Switch-2 (config-if) switchport mode access
• Switch-2 (config-if) switchport access vlan 10
• Switch-2(config)interface fastethernet 0/2
• Switch-2 (config-if) switchport mode access
• Switch-2 (config-if) switchport access vlan 20
• Switch-2(config)interface fastethernet 0/24
• Switch-2(config-if)shutdown
• Switch-2(config-if)switchport trunk
  encapsulation dot1q
• Switch-2(config-if)switchport trunk allowed vlan
  99,10,20
• Switch-2(config-if)switchport mode trunk
• Switch-2(config-if)switchport trunk native vlan
  99
• Switch-2(config-if)switchport nonegotiate
• Switch-2(config-if)no shutdown

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VLAN Hopping
Function

• VLAN hopping can be used to steal passwords and
  other sensitive information from specific network
  subscribers. VLAN hopping can also be used to
  modify, corrupt, or delete data, install spyware
  or other malware programs, and propagate viruses,
  worms, and Trojans throughout a network.
• This example can be applied to all the Cisco
  switches, like Catalyst 2960, 3560 series switch,
  Cisco 3750X, 3850 Cisco, etc.

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Contact Us

• Website http//www.router-switch.com/
• Tel [phone] (USA) 852-9795-4940 /
  852-3174-6166 (Hong Kong)
• Fax [phone] (Hong Kong)
• Email cisco_at_router-switch.com (Sales Inquiries)