Advanced Security Configuration
155
Table 84. Advanced Security Configuration Fields
Click
Apply
to save any changes for the current boot session. The changes take effect immediately but
are not retained across a switch reset unless you click
Save Configuration
.
Field
Description
Auto DoS Features
Auto DoS
Enable this option to enable all the DoS prevention mechanisms with default values. Enabling
this feature makes all the fields in the remainder of the table inaccessible (grayed-out). When
disabled, you can individually turn on and off the DoS features and change their default
values. This feature and all the individual DoS protections are disabled by default.
Prevent Land Attack
Enable this option to drop packets for which the source IP address equals the destination IP
address.
Prevent TCP Blat Attack
Enable this option to drop packets for which the TCP source port equals the TCP destination
port.
Prevent UDP Blat Attack
Enable this option to drop packets that have a UDP source port equal to the UDP destination
port.
Prevent Invalid TCP Flags
Attack
Enable this option to drop packets that have TCP Flags SYN and FIN set.
Prevent TCP Fragment
Attack
Enable this option to drop IP packets that have an IP fragment offset equal to 1.
Check First Fragment Only
Enable this option to drop packets that have a TCP header smaller than the minimum TCP
header size, which is hard-coded to 20 bytes.
Prevent Smurf Attack
Enable this option to drop ICMP Echo packets (ping) that are sent to a broadcast IP address.
Prevent Ping Flood Attack
Enable this option to prevent ping flooding by limiting the number of ICMP ping packets.
Prevent SYN Flood Attack
Enable this option to limit the rate of TCP connection requests so that they are not received
faster than they can be processed.
ICMP Settings
ICMP
Enable this option to allow the device to drop ICMP packets that have a type set to
ECHO_REQ (ping) and a payload size greater than the ICMP payload size configured in the
Max ICMPv4 Size or Max ICMPv6 Size fields.
Max ICMPv4 Size
The maximum allowed ICMPv4 packet size. If ICMP DoS prevention is enabled, the device
will drop ICMPv4 ping packets that have a size greater then this configured maximum
ICMPv4 packet size.
ICMPv6
Enable this option to allow the device to drop ICMP packets that have a type set to
ECHO_REQ (ping) and a payload size greater than the ICMP payload size configured in the
Max ICMPv6 Size field
Max ICMPv6 Size
The maximum allowed IPv6 ICMP packet size. If ICMP DoS prevention is enabled, the switch
will drop IPv6 ICMP ping packets that have a size greater than this configured maximum
ICMPv6 packet size.
ICMP Fragment
Enable this option to allow the device to drop fragmented ICMP packets.