D-Link DGS-6600-48TS Configuration Guide - Page 475

Safeguard Engine Settings, Overview, An Introduction to Safeguard Engine Settings

Page 475 highlights

Volume 8-Safeguard Engine / Chapter 47-Safeguard Engine Settings Chapter Overview Chapter 47 Safeguard Engine Settings Chapter Overview The following topics are included in this chapter, please go to the topic for more detailed information: • Chapter Overview • An Introduction to Safeguard Engine Settings • In Fuzzy mode, once the Safeguard Engine has entered the Exhausted mode, the Safeguard Engine will decrease the packet flow by half. After returning to Normal mode, the packet flow will be increased by 25%. The switch will then return to its interval checking and dynamically adjust the packet flow to avoid overload of the Switch. • Configuration Commands • Configuration Command Examples An Introduction to Safeguard Engine Settings Periodically, malicious hosts on the network will attack Switches by utilizing packet flooding (ARP Storm) or other attack methods and these attacks may increase the switch load beyond its capability. To alleviate this problem, the Safeguard Engine function was added to the DGS-6600. The Safeguard Engine can help the overall operability of the Switch by minimizing the workload of the Switch while the attack is ongoing, thus making it capable to forward essential packets over its network in a limited bandwidth. The Safeguard Engine has two operating modes that can be configured by the user, Strict and Fuzzy. In Strict mode, when the Switch either (a) receives too many packets to process or (b) exerts too much memory, it will enter the Exhausted mode. When in this mode, the Switch will drop all ARP and IP broadcast packets and packets from un-trusted IP addresses for a calculated time interval. Every five seconds, the Safeguard Engine will check to see if there are too many packets flooding the Switch. If the threshold has been crossed, the Switch will initially stop all ingress ARP and IP broadcast packets and packets from un-trusted IP addresses for five seconds. After another five-second checking interval arrives, the Switch will again check the ingress flow of packets. If the flooding has stopped, the Switch will again begin accepting all packets. Yet, if the checking shows that there continues to be too many packets flooding the Switch, it will stop accepting all ARP and IP broadcast packets and packets from un-trusted IP addresses for double the time of the previous stop period. This doubling of time for stopping these packets will continue until the maximum time has been reached, which is 320 seconds and every stop from this point until a return to normal ingress flow would be 320 seconds. For a better understanding, see the figure below. DGS-6600 Configuration Guide 475

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Volume 8-Safeguard Engine / Chapter 47-Safeguard Engine Settings
Chapter Overview
DGS-6600 Configuration Guide
475
Safeguard Engine Settings
Chapter Overview
The following topics are included in this chapter, please go to the topic for more detailed information:
Chapter Overview
An Introduction to Safeguard Engine Settings
In Fuzzy mode, once the Safeguard Engine has entered the Exhausted mode, the
Safeguard Engine will decrease the packet flow by half. After returning to Normal
mode, the packet flow will be increased by 25%. The switch will then return to its inter-
val checking and dynamically adjust the packet flow to avoid overload of the Switch.
Configuration Commands
Configuration Command Examples
An Introduction to Safeguard Engine Settings
Periodically, malicious hosts on the network will attack Switches by utilizing packet flooding (ARP
Storm) or other attack methods and these attacks may increase the switch load beyond its
capability. To alleviate this problem, the Safeguard Engine function was added to the DGS-6600.
The Safeguard Engine can help the overall operability of the Switch by minimizing the workload of
the Switch while the attack is ongoing, thus making it capable to forward essential packets over its
network in a limited bandwidth. The Safeguard Engine has two operating modes that can be
configured by the user, Strict and Fuzzy. In Strict mode, when the Switch either (a) receives too
many packets to process or (b) exerts too much memory, it will enter the Exhausted mode. When in
this mode, the Switch will drop all ARP and IP broadcast packets and packets from un-trusted IP
addresses for a calculated time interval. Every five seconds, the Safeguard Engine will check to see
if there are too many packets flooding the Switch. If the threshold has been crossed, the Switch will
initially stop all ingress ARP and IP broadcast packets and packets from un-trusted IP addresses for
five seconds. After another five-second checking interval arrives, the Switch will again check the
ingress flow of packets. If the flooding has stopped, the Switch will again begin accepting all
packets. Yet, if the checking shows that there continues to be too many packets flooding the Switch,
it will stop accepting all ARP and IP broadcast packets and packets from un-trusted IP addresses for
double the time of the previous stop period. This doubling of time for stopping these packets will
continue until the maximum time has been reached, which is 320 seconds and every stop from this
point until a return to normal ingress flow would be 320 seconds. For a better understanding, see the
figure below.
Chapter 47