B-14
Cisco Intrusion Prevention System Sensor CLI Configuration Guide for IPS 7.2
OL-29168-01
AppendixB Signature Engines
Atomic Engine
For more information on the parameters common to all signature engines, see Master Engine,
page B-4.
Atomic Engine
The Atomic engine contains signatures for simple, single packet conditions that cause alerts to be fired.
This section describes the Atomic engine, and contains the following topics:
Atomic ARP Engine, page B-14
Atomic IP Advanced Engine, pageB-15
Atomic IP Engine, page B-25
Atomic IPv6 Engine, page B-29

Atomic ARP Engine

The Atomic ARP engine defines basic Layer 2 ARP signatures and pr ovides more advanced detection
of the ARP spoof tools dsniff and ettercap.
Tabl e B-7 lists the parameters that are specific to the Atomic ARP engine.
TableB-7 Atomic ARP Engine Parameters
Parameter Description Value
specify-arp-operation {yes | no} (Optional) Enables A RP operation:
arp-operation—Specifies the type of ARP
operation to inspect.
0 to 65535
specify-mac-flip {yes | no} (Optional) Enables MAC address flip times:
mac-flip—Specifies how many times to flip
the MAC address in the alert.
0 to 65535
specify-request-inbalance {yes |
no}
(Optional) Enables request inbalance:
request-inbalance—Specifies the value for
firing an alert when there are this many more
requests than replies on the IP address.
0 to 65535