H3C Technologies H3C SecBlade LB Cards - Manual (Page 258)

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Step Command Remarks
8. Enable the blacklist
function.
blacklist enable
Required to make the blacklist entries
added by the scanning attack
protection function take effect.
By default, the blacklist function is
disabled.
Configuring a flood attack protection policy
The flood attack protection function is mainly used to protect servers. It detects various flood attacks by
monitoring the rate at which connection requests are sent to a server. The flood attack protection function
is usually applied to the security zones connecting the internal network and inspects only the outbound
packets of the security zones.
With flood attack protection enabled, the device is in attack detection state. When the device detects that
the rate of sending connection requests to a server constantly reaches or exceeds the specified action
threshold, the device considers the server is under attack and enters the attack protection state. Then, the
device takes protection actions as configured (by default, the device only outputs alarm logs, but can be
configured to drop the subsequent connection request packets or use the TCP proxy as well). When the
device detects that the packet sending rate to the server drops below the silence threshold, it considers
that the attack to the server is over, turns back to the attack detection state, and stops taking the protection
actions.
You can configure attack protection for specific IP addresses. For IP addresses for which you do not
configure attack protection specifically, the device uses the global attack protection settings.
To configure a SYN flood attack protection policy:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter VD system view. switchto vd vd-name Required for a non-default VD.
3. Enter attack protection
policy view. attack-defense policy
policy-number
N/A
4. Enable SYN flood attack
protection.
defense syn-flood enable Disabled by default.
5. Configure the global action
and silence thresholds for
SYN flood attack protection.
defense syn-flood rate-threshold
high rate-number [ low
rate-number ]
Optional.
By default, the action threshold is
1000 packets per second and the
silence threshold is 750 packets per
second.
6. Configure the action and
silence thresholds for SYN
flood attack protection of a
specific IP address.
defense syn-flood ip ip-address
rate-threshold high rate-number
[ low rate-number ]
Optional.
Not configured by default.
7. Configure the device to drop
SYN flood attack packets or
use the TCP proxy.
defense syn-flood action
{ drop-packet | trigger-tcp-proxy }
Optional.
By default, the device only outputs
alarm logs if detecting an attack.
To configure an ICMP flood attack protection policy: