Example for Configuring DHCP Snooping Attack Defense

CloudEngine 12800 and 12800E V200R005C10 Configuration Guide - Security

This document describes the configurations of Security, including AAA, 802.1x Authentication, ACL, TCAM ACL Customization, local attack defense, Microsegmentation, MFF, attack defense, traffic suppression and storm control, ARP security, Port security, MACsec, DHCP snooping, IPSG, URPF, SSL, Keychain and FIPS.

About This Document
AAA Configuration
- Overview of AAA
- Understanding AAA
- Application Scenarios for AAA
- Licensing Requirements and Limitations for AAA
- Summary of AAA Configuration Tasks
- Configuring Local Authentication and Authorization
- Configuring RADIUS AAA
- Configuring HWTACACS AAA
- Clearing AAA Statistics
- Configuration Examples for AAA
  - Example for Configuring RADIUS Authentication and Accounting
  - Example for Configuring HWTACACS Authentication, Accounting, and Authorization
- Troubleshooting AAA
  - An AAA Local User Cannot Be Created Due to Incorrect Password Setting
802.1x Authentication Configuration
- Understanding 802.1x Authentication
- Application Scenarios for 802.1x Authentication
- Licensing Requirements and Limitations for 802.1x Authentication
- Default Settings for 802.1x Authentication
- Configuring 802.1x Authentication
- Maintaining 802.1x Authentication
  - Clearing Statistics on 802.1x Authentication Packets
  - Forcing Users Offline
- Configuration Examples for 802.1x Authentication
  - Example for Configuring 802.1x Authentication to Control Users' Internal Access
ACL Configuration
- Overview of ACLs
- Understanding ACLs
- Application Scenarios for ACLs
- Licensing Requirements and Limitations for ACLs
- Default Settings for ACLs
- Configuring a Basic ACL
- Configuring an Advanced ACL
- Configuring a Layer 2 ACL
- Configuring a User-defined ACL
- Configuring an ARP-based ACL
- Configuring a Basic ACL6
- Configuring an Advanced ACL6
- Maintaining an ACL
  - Clearing ACL Statistics
  - Checking ACL Resource Usages
- Configuration Examples for ACLs
- ACL FAQ
  - Which Packets Cannot Be Filtered by the ACL Used by a Traffic Policy?
TCAM ACL Customization Configuration
- Overview of TCAM ACL Customization
- Licensing Requirements and Limitations for TCAM ACL Customization
- Configuring TCAM ACL Customization
  - Enabling TCAM ACL Customization
  - Configuring the TCAM ACL Customization Function for Services
- Displaying Information about a TCAM ACL Customization Profile or Preset Profile
- Configuration Examples for TCAM ACL Customization
  - Example for Configuring TCAM ACL Customization
Microsegmentation Configuration
- Overview of Microsegmentation
- Understanding Microsegmentation
- Application Scenarios for Microsegmentation
- Licensing Requirements and Limitations for Microsegmentation
- Configuring Microsegmentation
- Maintaining Microsegmentation
  - Checking Microsegmentation Statistics
  - Clearing Microsegmentation Statistics
- Configuration Examples for Microsegmentation
  - Example for Configuring IP Address-based Microsegmentation
Local Attack Defense Configuration
- Overview of Local Attack Defense
- Licensing Requirements and Limitations for Local Attack Defense
- Default Settings for Local Attack Defense
- Configuring CPU Attack Defense
- Configuring Attack Source Tracing
- Maintaining Local Attack Defense
- Configuration Examples for Local Attack Defense
  - Example for Configuring Local Attack Defense
- Troubleshooting Local Attack Defense
MFF Configuration
- Overview of MFF
- Understanding MFF
- Application Scenarios for MFF
- Licensing Requirements and Limitations for MFF
- Configuring MFF
- Configuration Examples for MFF
  - Example for Configuring MFF to Implement Layer 2 Isolation and Layer 3 Connection
- Troubleshooting MFF
  - Users Fail to Access the Internet After MFF Is Configured
Attack Defense Configuration
- Overview of Attack Defense
- Understanding Attack Defense
- Application Scenarios for Attack Defense
- Licensing Requirements and Limitations for Attack Defense
- Default Settings for Attack Defense
- Configuring Defense Against Malformed Packet Attacks
- Configuring Defense Against Packet Fragment Attacks
- Configuring Defense Against Flood Attacks
- Clearing Attack Defense Statistics
- Configuration Examples for Attack Defense
  - Example for Configuring Attack Defense
Traffic Suppression and Storm Control Configuration
- Overview of Traffic Suppression and Storm Control
- Understanding Traffic Suppression and Storm Control
  - Traffic Suppression
  - Storm Control
- Application Scenarios for Traffic Suppression and Storm Control
  - Traffic Suppression
  - Storm Control
- Licensing Requirements and Limitations for Traffic Suppression and Storm Control
- Default Settings for Traffic Suppression and Storm Control
- Configuring Traffic Suppression
- Configuring Storm Control
- Configuration Examples for Traffic Suppression and Storm Control
  - Example for Configuring Traffic Suppression
  - Example for Configuring Storm Control
ARP Security Configuration
- Overview of ARP Security
- Understanding ARP Security
- Application Scenarios for ARP Security
  - Defense Against ARP Flood Attacks
  - Defense Against ARP Spoofing Attacks
- Licensing Requirements and Limitations for ARP Security
- Default Settings for ARP Security
- Configuring Defense Against ARP Flood Attacks
- Configuring Defense Against ARP Spoofing Attacks
- Maintaining ARP Security
- Configuration Examples for ARP Security
  - Example for Configuring ARP Security Functions
  - Example for Configuring Defense Against ARP MITM Attacks
Port Security Configuration
- Overview of Port Security
- Understanding Port Security
- Application Scenarios for Port Security
- Licensing Requirements and Limitations for Port Security
- Default Settings for Port Security
- Configuring Port Security
- Configuration Examples for Port Security
  - Example for Configuring Port Security
MACsec Configuration
- Overview of MACsec
- Understanding MACsec
- Application Scenarios for MACsec
- Default Configuration
- Licensing Requirements and Limitations for MACsec
- Configuring MACsec
- Maintaining MACsec
  - Displaying MACsec Statistics
  - Clearing MACsec Statistics
- Configuration Examples for MACsec
  - Example for Configuring Point-to-Point MACsec
DHCP Snooping Configuration
- Overview of DHCP Snooping
- Understanding DHCP Snooping
  - DHCP Snooping Fundamentals
  - Option 82 Supported by DHCP Snooping
- Application Scenarios for DHCP Snooping
- Licensing Requirements and Limitations for DHCP Snooping
- Default Settings for DHCP Snooping
- Configuring Basic Functions of DHCP Snooping
- Configuring DHCP Snooping Attack Defense
- Inserting the Option 82 Field in a DHCP Message
- Maintaining DHCP Snooping
- Configuration Examples for DHCP Snooping
  - Example for Configuring DHCP Snooping Attack Defense
- Troubleshooting DHCP Snooping
  - DHCP Clients Cannot Go Online Due to DHCP Snooping
IPSG Configuration
- Overview of IPSG
- Licensing Requirements and Limitations for IPSG
- Default Settings for IPSG
- Configuring IPSG
- Maintaining IPSG
  - Checking Statistics on Discarded IP Packets
  - Clearing Statistics on Discarded IP Packets
- Configuration Examples for IPSG
  - Example for Configuring IPSG to Check Interface + IP + MAC Binding Entries
URPF Configuration
- Overview of URPF
- Understanding URPF
- Application Scenarios for URPF
- Licensing Requirements and Limitations for URPF
- Default Settings for URPF
- Configuring URPF
- Configuration Examples for URPF
  - Example for Configuring URPF (CE12800)
  - Example for Configuring URPF (CE12800E)
SSL Configuration
- Overview of SSL
- Understanding SSL
- Application Scenarios for SSL
  - Application of SSL in Information Center
- Licensing Requirements and Limitations for SSL
- Configuring SSL
  - Configuring an SSL Policy
  - Applying an SSL Policy
- Configuration Examples for SSL
  - Example for Outputting SSL-Encrypted Logs to a Log Host
Keychain Configuration
- Overview of Keychains
- Understanding Keychains
- Application Scenarios for Keychains
- Licensing Requirements and Limitations for Keychain
- Configuring a Keychain
- Configuration Examples for Keychains
  - Example for Applying the Keychain to RIP
  - Example for Applying the Keychain to BGP
FIPS Configuration
- Overview of FIPS
- Configuring the FIPS Mode
Separating the Management Port from the Service Plane
Checking Security Risks
Setting the System Master Key

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Example for Configuring DHCP Snooping Attack Defense

Networking Requirements

In Figure 13-6, SwitchA and SwitchB are access devices, and SwitchC is a DHCP relay agent. Client1 and Client2 are connected to SwitchA through 10GE1/0/1 and 10GE1/0/2 respectively. Client3 is connected to SwitchB through 10GE1/0/1. Client1 and Client3 obtain IP addresses using DHCP, while Client2 uses the static IP address. Attacks from unauthorized users prevent authorized users from obtaining IP addresses. The administrator needs to enable the device to defend against DHCP attacks on the network and provide better service to DHCP clients.

Figure 13-6 Networking diagram for configuring DHCP snooping attack defense

Configuration Roadmap

The configuration roadmap is as follows:

Enable DHCP snooping.
Configure an interface as the trusted interface to ensure that DHCP clients obtain IP addresses from the authorized server.
Enable association between ARP and DHCP snooping to enable the device to update the binding entries when a DHCP user is disconnected.
Enable the device to check DHCP messages against the binding table to prevent bogus DHCP message attacks.
Set the maximum rate of sending DHCP messages to the processing unit to prevent DHCP flood attacks.
Set the maximum number of access DHCP clients and enable the device to check whether the MAC address in the Ethernet frame header matches the CHADDR field in the DHCP message to prevent DHCP server DoS attacks.
Configure the trap function for the number of discarded messages and the rate limit.

Procedure

Enable DHCP snooping.

# Enable DHCP snooping globally.

<HUAWEI> system-view
[~HUAWEI] sysname SwitchC
[*HUAWEI] commit
[~SwitchC] dhcp enable
[*SwitchC] dhcp snooping enable

# Enable DHCP snooping on the user-side interface. 10GE1/0/1 is used as an example. The configuration on 10GE1/0/2 is the same as the configuration on 10GE1/0/1 and is not mentioned here.

[*SwitchC] interface 10ge 1/0/1
[*SwitchC-10GE1/0/1] dhcp snooping enable
[*SwitchC-10GE1/0/1] quit

Configure the interface connected to the DHCP server as the trusted interface.

[*SwitchC] interface 10ge 2/0/1
[*SwitchC-10GE2/0/1] dhcp snooping trusted
[*SwitchC-10GE2/0/1] quit

Enable association between ARP and DHCP snooping.

[*SwitchC] dhcp snooping user-bind arp-detect enable

Enable the device to check DHCP messages against the DHCP snooping binding table.
# Configure the user-side interface. 10GE1/0/1 is used as an example. The configuration on 10GE1/0/2 is the same as the configuration on 10GE1/0/1 and is not mentioned here.
```
[*SwitchC] interface 10ge 1/0/1
[*SwitchC-10GE1/0/1] dhcp snooping check binding enable
[*SwitchC-10GE1/0/1] quit
```

Set the maximum rate of sending DHCP messages to the processing unit to 90 pps.

[*SwitchC] dhcp snooping rate-limit enable
[*SwitchC] dhcp snooping rate-limit 90

Set the maximum number of access users allowed on the interface and enable the device to check the CHADDR field.
# Configure the user-side interface. 10GE1/0/1 is used as an example. The configuration on 10GE1/0/2 is the same as the configuration on 10GE1/0/1 and is not mentioned here.
```
[*SwitchC] interface 10ge 1/0/1
[*SwitchC-10GE1/0/1] dhcp snooping user-bind max-number 20
[*SwitchC-10GE1/0/1] dhcp snooping check mac-address enable
[*SwitchC-10GE1/0/1] quit
```

Configure the trap function for the number of discarded messages and the rate limit.

# Enable the trap function for discarding messages and set the alarm threshold. 10GE1/0/1 is used as an example. The configuration on 10GE1/0/2 is the same as the configuration on 10GE1/0/1 and is not mentioned here.

[*SwitchC] interface 10ge 1/0/1
[*SwitchC-10GE1/0/1] dhcp snooping alarm mac-address enable
[*SwitchC-10GE1/0/1] dhcp snooping alarm binding enable
[*SwitchC-10GE1/0/1] dhcp snooping alarm untrust-reply enable
[*SwitchC-10GE1/0/1] dhcp snooping alarm mac-address threshold 120
[*SwitchC-10GE1/0/1] dhcp snooping alarm binding threshold 120
[*SwitchC-10GE1/0/1] dhcp snooping alarm untrust-reply threshold 120
[*SwitchC-10GE1/0/1] quit

# Enable the trap function for the rate limit and set the alarm threshold.

[*SwitchC] dhcp snooping alarm rate-limit enable
[*SwitchC] dhcp snooping alarm rate-limit threshold 500
[*SwitchC] commit

Verify the configuration.

# Run the display dhcp snooping interface command to view DHCP snooping information on an interface.

[~SwitchC] display dhcp snooping interface 10ge 1/0/1
 DHCP snooping                            : Enable                              
 Trusted interface                        : No                                  
 DHCP user max number                     : 20                                  
 Current DHCP user number                 : 0                                   
 Check MAC-address                        : Enable                              
 Alarm MAC-address                        : Enable                              
 Alarm MAC-address threshold              : 120                                 
 Discarded packets for check MAC-address  : 0                                   
 Check binding                            : Enable                              
 Alarm binding                            : Enable                              
 Alarm binding threshold                  : 120                                 
 Discarded packets for check binding      : 0                                   
 Rate-limit                               : Disable  (default)                  
 Alarm rate-limit                         : Disable  (default)                  
 Alarm rate-limit threshold               : 500                                 
 Discarded packets for rate-limit         : 0                                   
 Alarm untrust-reply                      : Enable                              
 Alarm untrust-reply threshold            : 120                                 
 Discarded packets for check untrust-reply: 0                                   
[~SwitchC] display dhcp snooping interface 10ge 2/0/1
 DHCP snooping                            : Disable  (default)                               
 Trusted interface                        : Yes                                  
 DHCP user max number                     : 32768    (default)                  
 Current DHCP user number                 : 0                                   
 Check MAC-address                        : Disable  (default)                  
 Alarm MAC-address                        : Disable  (default)                  
 Check binding                            : Disable  (default)                  
 Alarm binding                            : Disable  (default)                  
 Rate-limit                               : Disable  (default)                  
 Alarm rate-limit                         : Disable  (default)                  
 Alarm rate-limit threshold               : 500                                 
 Discarded packets for rate-limit         : 0                                   
 Alarm untrust-reply                      : Disable  (default)

Configuration Files

# Configuration file of the SwitchC

#                                                                               
sysname SwitchC
#                                                                               
dhcp enable                                                                     
#                                                                               
dhcp snooping enable                                                            
dhcp snooping rate-limit enable                                            
dhcp snooping rate-limit 90                                                
dhcp snooping alarm rate-limit enable                                            
dhcp snooping alarm rate-limit threshold 500                                      
dhcp snooping user-bind arp-detect enable
#
interface 10GE1/0/1
 dhcp snooping enable                                                           
 dhcp snooping check binding enable                                           
 dhcp snooping alarm binding enable                                           
 dhcp snooping alarm binding threshold 120                                    
 dhcp snooping check mac-address enable                                         
 dhcp snooping alarm mac-address enable                                         
 dhcp snooping alarm mac-address threshold 120                                  
 dhcp snooping alarm untrust-reply enable                                       
 dhcp snooping alarm untrust-reply threshold 120                                
 dhcp snooping user-bind max-number 20   
#
interface 10GE1/0/2
 dhcp snooping enable                                                           
 dhcp snooping check binding enable                                           
 dhcp snooping alarm binding enable                                           
 dhcp snooping alarm binding threshold 120                                    
 dhcp snooping check mac-address enable                                         
 dhcp snooping alarm mac-address enable                                         
 dhcp snooping alarm mac-address threshold 120                                  
 dhcp snooping alarm untrust-reply enable                                       
 dhcp snooping alarm untrust-reply threshold 120                                
 dhcp snooping user-bind max-number 20   
#
interface 10GE2/0/1
 dhcp snooping trusted
#
return

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Updated: 2021-09-17

Document ID: EDOC1100075347

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