Dell PowerConnect 8024 User's Guide - Page 22

Switching Features PHY Power Down/Low Power on Pre-Link This feature provides a low-power mode. When the low-power mode is enabled and no link partner is detected, the PHY automatically goes into a low power mode. When the PHY detects a link partner, it returns to the "normal" power mode. IPv6 Access Control Lists An IPv6 ACL consists of a set of rules which are matched sequentially against a packet. When a packet meets the match criteria of a rule, the specified rule action (Permit/Deny) is taken and the additional rules are not checked for a match. Access Control List (ACL) Outbound Support This feature enables binding an ACL (IP, MAC, or IPv6) in outbound direction on physical, LAG, and VLAN interfaces. IP Source Guard (IPSG) IP source guard (IPSG) is a security feature that filters IP packets based on the source ID. The source ID may either be source IP address or a source IP address source MAC address pair. IPSG is disabled by default. DHCP Snooping DHCP Snooping is a security feature that monitors DHCP messages between a DHCP client and DHCP server. It filters harmful DHCP messages and builds a bindings database of (MAC address, IP address, VLAN ID, port) tuples that are specified as authorized. DHCP snooping can be enabled globally and on specific VLANs. Ports within the VLAN can be configured to be trusted or untrusted. DHCP servers must be reached through trusted ports. DHCP L2 Relay This feature permits L3 Relay agent functionality in L2 switched networks. Dynamic ARP Inspection Dynamic ARP Inspection (DAI) is a security feature that rejects invalid and malicious ARP packets. The feature prevents a class of man-in-the-middle attacks, where an unfriendly station intercepts traffic for other stations by poisoning the ARP caches of its unsuspecting neighbors. The miscreant sends ARP requests or responses mapping another station's IP address to its own MAC address. Dynamic ARP Inspection relies on DHCP Snooping. 22 Introduction