Reference: Configuration options
Avira Professional Security - User Manual (Status: 23 Sep. 2011)
120
Note
The default
Security level
setting for all predefined rules of the Avira FireWall is
Medium.
ICMP protocol
The Internet Control Message Protocol (ICMP) is used to exchange error and information
messages on networks. The protocol is also used for status messages with ping or tracer.
With this rule, you can define the incoming and outgoing blocked message types, the
behavior in case of flooding and the reaction to fragmented ICMP packets. This rule
serves for preventing so-called ICMP flood attacks, which results in an increase of the
CPU load of the attacked machine as it responds to every packet.
Predefined rules for the ICMP protocol
Setting
Rules
Low
Incoming blocked types:
no type
.
Outgoing blocked types:
no type
.
Assume flooding if delay between packets is less than
50
ms.
Reject
fragmented ICMP packets.
Medium
Same rule as for the Low level.
High
Incoming blocked types:
several types
Outgoing blocked types:
several types
Assume flooding if delay between packets is less than
50
ms.
Reject
fragmented ICMP packets.
Incoming blocked types: no types/several types
With a mouse click on the link a list of ICMP packet types is displayed. From this list
you can specify the desired incoming ICMP message types you want to block.
Outgoing blocked types: no types/several types
With a mouse click on the link a list of ICMP packet types is displayed. From this list
you can select the desired outgoing ICMP message types you want to block.
