IP Source Guard

Table 1. IP Source Guard product support
Feature	Product	Release introduced
IP Source Guard (IPv4)	5320 Series	Fabric Engine 8.6
	5420 Series	VOSS 8.4
	5520 Series	VOSS 8.2.5
	5720 Series	Fabric Engine 8.7
IP Source Guard (IPv6)	5320 Series	Fabric Engine 8.6
	5420 Series	VOSS 8.4
	5520 Series	VOSS 8.2.5
	5720 Series	Fabric Engine 8.7

IP Source Guard (IPSG) is a Layer 2 port-to-port feature that works closely with DHCP Snooping. It prevents IP spoofing by allowing only IP addresses obtained using DHCP Snooping. When you enable IPSG on an untrusted port with DHCP Snooping enabled, an IP filter is automatically created or deleted for that port based on the information stored in the corresponding DHCP Snooping binding table entry. When a connecting client receives a valid IP address from the DHCP server, the filter installed on the port allows traffic only from that assigned IP address.

You can configure IPSG on a port using the command line interface (CLI), the Enterprise Device Manager (EDM), or SNMP.

Note

The switch supports configuration of IP Source Guard for both IPv4 and IPv6 addresses.

The following table shows how IPSG works with DHCP Snooping.

Table 2. IP Source Guard and DHCP snooping
IP Source Guard configuration state	DHCP snooping configuration state	DHCP snooping Binding Entry action (untrusted ports)	IP Source Guard action
change from disabled to enabled	enabled	creates a binding entry	creates a filter for the IP address using the IP address from the binding table entry
enabled	enabled	creates a binding entry	creates a filter for the IP address using the IP address from the binding table entry
enabled	enabled	deletes a binding entry	deletes the IP filter and installs a default filter to block all IP traffic on the port
enabled	enabled	deletes binding entries when one of the following conditions occur: a DHCP release packet is received the port link is down the lease time has expired the port is removed from the VLAN the VLAN is deleted the port is set as trusted the binding entries are manually deleted	deletes the corresponding IP filter and installs a default filter to block all IP traffic
change from enabled to disabled	enabled	not applicable	deletes the installed IP filter for the port
disabled	enabled	creates a binding entry
disabled	enabled	deletes a binding entry