H3C S12500R Series Quick guide

H3C S12500R Switch Router Series
Attack Protection Configuration Examples
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Contents
Introduction····································································································1
Prerequisites··································································································1
Example: Configuring link layer attack protection···········································2
Network configuration ········································································································································2
Analysis······························································································································································3
Software versions used······································································································································3
Restrictions and guidelines································································································································3
Procedures·························································································································································3
Configuring Device B ·································································································································3
Configuring Device A ·································································································································3
Configuring Device C·································································································································4
Verifying the configuration··································································································································5
Configuration files ··············································································································································5
Example: Configuring ARP attack protection·················································6
Network configuration ········································································································································6
Software versions used······································································································································7
Procedures·························································································································································7
Verifying the configuration··································································································································7
Configuration files ··············································································································································8
Example: Configuring network layer attack protection ···································8
Network configuration ········································································································································8
Software versions used······································································································································8
Restrictions and guidelines································································································································9
Procedures·························································································································································9
Verifying the configuration··································································································································9
Configuration files ··············································································································································9
Example: Configuring transport layer attack protection································10
Network configuration ······································································································································10
Software versions used····································································································································10
Procedures·······················································································································································10
Verifying the configuration································································································································10
Configuration files ············································································································································11
Related documentation················································································11

1
Introduction
This document provides configuration examples of link layer attack protection, ARP attack protection,
network layer attack protection, and transport layer attack protection, as defined in Table 1.
Table 1 Attack protection types
Attack protection types
Description
Link layer attack
protection
MAC address attack
protection
Prevents the attack of packets with different source
MAC addresses or VLANs by configuring the
maximum number of MAC addresses that an
interface can learn.
STP packet attack protection Provides protection measures such as BPDU guard,
root guard, loop guard, and TC-BPDU guard.
ARP attack
protection
ARP source suppression Prevents IP attack packets from fixed sources.
ARP black hole routing Prevents IP attack packets from sources that are not
fixed.
ARP active
acknowledgement Prevents user spoofing.
Source MAC-based ARP
attack detection Prevents ARP packet attacks from the same source MAC.
ARP packet source MAC
consistency check
Prevents attacks from ARP packets whose source
MAC address in the Ethernet header is different from
the sender MAC address in the message body.
Network layer
attack protection
uRPF check Protects a network against source spoofing attacks.
TTL attack protection Prevents an attack by disabling sending ICMP time
exceeded messages.
Transport layer
attack protection SYN flood attack protection Enables the server to return a SYN ACK message
when it receives a TCP connection request, without
establishing a half-open TCP connection.
Prerequisites
The configuration examples in this document were created and verified in a lab environment, and all
the devices were started with the factory default configuration. When you are working on a live
network, make sure you understand the potential impact of every command on your network.
This document assumes that you have basic knowledge of attack protection.

2
Example: Configuring link layer attack
protection
Network configuration
As shown in Figure 1, Device A, Device B, and Device C run MSTP. Device B acts as the root bridge,
and HundredGigE 1/0/1 on Device C is blocked.
Configure the following features to prevent link layer attacks:
•
Configure root guard on HundredGigE 1/0/1 and HundredGigE 1/0/2 of Device B for Device B to
act as the root bridge.
•
Configure loop guard on HundredGigE 1/0/2 of Device C to prevent temporary loops. The loop
guard feature keeps the port in Discarding state in all MSTIs when it receives no BPDU.
•
Configure BPDU guard on ports at the access side of Device Aand Device C. The BPDU guard
feature prevents the ports from performing spanning tree calculations when it receives forged
BPDUs with a higher priority.
•
Enable TC-BPDU guard on Device A, Device B, and Device C. The TC-BPDU guard feature
prevents a large number of TC-BPDUs from affecting the network in a short time.
•
Configure broadcast and multicast suppression on the designated ports of Device B and all
ports on Device A and Device C. When incoming broadcast or multicast traffic exceeds the
threshold (6400 pps), an interface discards broadcast or multicast packets until the traffic drops
below the threshold.
Figure 1 Network diagram
Device A
Device B
Device C
HGE1/0/1 HGE1/0/2
HGE1/0/1 HGE1/0/2
HGE1/0/2 HGE1/0/1
Dep 1 Dep 2 Dep 3 Dep 4 Dep 5
Network
HGE1/0/3 HGE1/0/3

3
Analysis
For the ports at the access side of Device A and Device C to rapidly transit to the forwarding state,
use the stp edged-port command to configure these ports as edge ports.
This example uses HundredGigE 1/0/3 to illustrate the configuration on the ports at the access side
on Device A and Device C.
Software versions used
This configuration example was created and verified on Release 3606.
Restrictions and guidelines
On a port, the loop guard feature is mutually exclusive with the root guard feature or the edge port
setting.
Do not configure the loop guard feature on ports at the access side. Otherwise, the ports stay in
Discarding state in all MSTIs because they cannot receive BPDUs.
By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have
an interface operate, you must use the undo shutdown command to enable that interface.
Procedures
Configuring Device B
# Specify IP addresses for interfaces. (Details not shown.)
# Configure root guard on HundredGigE 1/0/1 and HundredGigE 1/0/2.
<DeviceB> system-view
[DeviceB] interface range hundredgige 1/0/1 to hundredgige 1/0/2
[DeviceB-if-range] port link-mode bridge
[DeviceB-if-range] stp root-protection
[DeviceB-if-range] quit
# Configure TC-BPDU guard.
[DeviceB] stp tc-protection
[DeviceB] stp tc-protection threshold 10
# Configure broadcast and multicast suppression on HundredGigE 1/0/1 and HundredGigE 1/0/2.
[DeviceB] interface range hundredgige 1/0/1 to hundredgige 1/0/2
[DeviceB-if-range] broadcast-suppression pps 6400
[DeviceB-if-range] multicast-suppression pps 6400
[DeviceB-if-range] quit
Configuring Device A
# Specify IP addresses for interfaces. (Details not shown.)
# Configure each interface to operate in Later 2 mode.
<DeviceA> system-view

4
[DeviceA] interface range hundredgige 1/0/1 to hundredgige 1/0/3
[DeviceA-if-range] port link-mode bridge
[DeviceA-if-range] quit
# Configure STP BPDU guard.
[DeviceA] stp bpdu-protection
# Configure HundredGigE 1/0/3 as an edge port.
[DeviceA] interface hundredgige 1/0/3
[DeviceA-HundredGigE1/0/3] stp edged-port
[DeviceA-HundredGigE1/0/3] quit
# Configure TC-BPDU guard.
[DeviceA] stp tc-protection
[DeviceA] stp tc-protection threshold 10
# Configure broadcast and multicast suppression on all ports.
[DeviceA] interface range hundredgige 1/0/1 to hundredgige 1/0/3
[DeviceA-if-range] broadcast-suppression pps 6400
[DeviceA-if-range] multicast-suppression pps 6400
[DeviceA-if-range] quit
Configuring Device C
# Specify IP addresses for interfaces. (Details not shown.)
# Configure each interface to operate in Later 2 mode.
<DeviceC> system-view
[DeviceC] interface range hundredgige 1/0/1 to hundredgige 1/0/3
[DeviceC-if-range] port link-mode bridge
[DeviceC-if-range] quit
# Configure STP BPDU guard.
[DeviceC] stp bpdu-protection
# Configure HundredGigE 1/0/3 as an edge port.
[DeviceC] interface hundredgige 1/0/3
[DeviceC-HundredGigE1/0/3] stp edged-port
[DeviceC-HundredGigE1/0/3] quit
# Configure loop guard on HundredGigE 1/0/2.
[DeviceC] interface hundredgige 1/0/2
[DeviceC-HundredGigE1/0/2] stp loop-protection
[DeviceC-HundredGigE1/0/2] quit
# Configure TC-BPDU guard.
[DeviceC] stp tc-protection
[DeviceC] stp tc-protection threshold 10
# Configure broadcast and multicast suppression on all ports.
[DeviceC] interface range hundredgige 1/0/1 to hundredgige 1/0/3
[DeviceC-if-range] broadcast-suppression pps 6400
[DeviceC-if-range] multicast-suppression pps 6400
[DeviceC-if-range] quit

5
Verifying the configuration
# Verify that the edge ports go down after they receives STP BPDUs. (Details not shown.)
# Bring the edge ports up by using the undo shutdown command. (Details not shown.)
# Verify that the root bridge ID of Device B does not change and that the STP topology remains
stable after STP BPDUs with higher priority are sent to the Device B. (Details not shown.)
# Verify that the devices do not refresh the FIB table frequently and that no serious packet loss
occurs after a large number of TC BPDUs are sent to the devices. (Details not shown.)
# Verify that the uplink ports are not flooded after a large number of broadcasts are sent to the edge
ports on device Aand Device C. (Details not shown.)
Configuration files
•
Device A:
#
stp bpdu-protection
stp tc-protection threshold 10
#
interface HundredGigE 1/0/1
port link-mode bridge
broadcast-suppression pps 6400
multicast-suppression pps 6400
#
interface HundredGigE 1/0/2
port link-mode bridge
broadcast-suppression pps 6400
multicast-suppression pps 6400
#
interface HundredGigE 1/0/3
port link-mode bridge
stp edged-port
broadcast-suppression pps 6400
multicast-suppression pps 6400
#
•
Device B:
#
stp tc-protection threshold 10
#
interface HundredGigE 1/0/1
port link-mode bridge
stp root-protection
broadcast-suppression pps 6400
multicast-suppression pps 6400
#
interface HundredGigE 1/0/2
port link-mode bridge
stp root-protection

6
broadcast-suppression pps 6400
multicast-suppression pps 6400
#
•
Device C:
#
stp bpdu-protection
stp tc-protection threshold 10
#
interface HundredGigE 1/0/1
port link-mode bridge
broadcast-suppression pps 6400
multicast-suppression pps 6400
#
interface HundredGigE 1/0/2
port link-mode bridge
stp loop-protection
broadcast-suppression pps 6400
multicast-suppression pps 6400
#
interface HundredGigE 1/0/3
port link-mode bridge
stp edged-port
broadcast-suppression pps 6400
multicast-suppression pps 6400
#
Example: Configuring ARP attack
protection
Network configuration
As shown in Figure 2, the device is the gateway for the internal network. Configure ARP attack
protection on the device to prevent ARP attacks.

7
Figure 2 Network diagram
Software versions used
This configuration example was created and verified on Release 3606.
Procedures
# Specify IP addresses for interfaces. (Details not shown.)
# Enable ARP source suppression.
<Device> system-view
[Device] arp source-suppression enable
# Configure the device to accept a maximum of 8 unresolvable packets per source IP address in 5
seconds.
[Device] arp source-suppression limit 8
# Enable ARP black hole routing to prevent unresolvable IP packet attacks.
[Device] arp resolving-route enable
# Enable ARP active acknowledgment to prevent user spoofing.
[Device] arp active-ack enable
# Configure source MAC-based ARP attack detection to prevent ARP packet attacks from the same
source MAC.
[Device] arp source-mac filter
[Device] arp source-mac threshold 25
# Enable ARP packet source MAC address consistency check to prevent attacks from ARP packets
with different source MAC addresses in the Ethernet header and in the message body.
[Device] arp valid-check enable
Verifying the configuration
1. Verify that ARP attack protection functions on the device:
# Send ARP attack packets to the device. (Details not shown.)
Device
Network

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# Verify that the CPU usage does not surge. (Details not shown.)
2. Verify that each ARP attack protection feature functions on the device (this example uses the
ARP source suppression feature):
# Send the device 20 forged packets with the same source IP address and unresolvable
destination IP addresses. (Details not shown.)
# Verify that the device stops resolving the packets after receiving 8 forged packets within 5
seconds. (Details not shown.)
# Verify the ARP source suppression configuration.
[Device] display arp source-suppression
ARP source suppression is enabled
Current suppression limit: 8
Current cache length: 16
Configuration files
#
arp valid-check enable
arp source-mac filter
arp source-mac threshold 25
arp active-ack enable
arp source-suppression enable
arp source-suppression limit 8
#
Example: Configuring network layer
attack protection
Network configuration
As shown in Figure 3, Device Ais the gatewayfor the internal network. To protect Device Aagainst IP
packet attacks from internal and external networks, configure the following network layer attack
protection features:
•
Configure strict uRPF check to prevent source address spoofing attacks.
•
Disabling sending ICMP time exceeded messages. The device will not be flooded by ICMP time
exceeded messages when receiving a large number of packets with TTL set to 1.
Figure 3 Network diagram
Software versions used
This configuration example was created and verified on Release 3606.
Switch Device A
IP network
Device B