Motorola EX-3524, Справочное руководство CLI

Страница: 264 / 617

Chapter 8
| General Security Measures
Denial of Service Protection
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Example
Console#show ip arp inspection vlan 1
VLAN ID DAI Status ACL Name ACL Status
-------- --------------- -------------------- --------------------
1 disabled sales static
Console#
Denial of Service Protection
A denial-of-service attack (DoS attack) is an attempt to block the services provided
by a computer or network resource. This kind of attack tries to prevent an Internet
site or service from functioning efficiently or at all. In general, DoS attacks are
implemented by either forcing the target to reset, to consume most of its resources
so that it can no longer provide its intended service, or to obstruct the
communication media between the intended users and the target so that they can
no longer communicate adequately.
This section describes commands used to protect against DoS attacks.
flow
tcp-udp-port-zero
This command protects against DoS attacks in which the UDP or TCP source port or
destination port is set to zero. This technique may be used as a form of DoS attack,
or it may just indicate a problem with the source device. Use the
no form to restore
the default setting.
Syntax
flow tcp-udp-port-zero { drop | forward }
no flow tcp-udp-port-zero
drop – Drops all packets with the Layer 4 source port or destination port
set to zero.
forward – Forwards all packets with the Layer 4 source port or destination
port set to zero.
Default Setting
Drop
Table 53: DoS Protection Commands
Command Function Mode
flow tcp-udp-port-zero Protects against attacks which set the Layer 4 source
or destination port to zero GC
show flow Shows the action taken against attacks which set
the Layer 4 source or destination port to zero PE