Web Management Guide-R04

Table Of Contents
Chapter 12
| Security Measures
IPv4 Source Guard
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Note:
Multicast addresses cannot be used by IP Source Guard.
When enabled, traffic is filtered based upon dynamic entries learned via DHCP
snooping (see “DHCPv4 Snooping” on page 368), or static addresses
configured in the source guard binding table.
If IP source guard is enabled, an inbound packet’s IP address (SIP option) or
both its IP address and corresponding MAC address (SIP-MAC option) will be
checked against the binding table. If no matching entry is found, the packet
will be dropped.
An entry with same MAC address and a diferent VLAN ID cannot be added to
the binding table .
Filtering rules are implemented as follows:
If DHCP snooping is disabled (see page 371), IPv4 source guard will check
the VLAN ID, source IP address, port number, and source MAC address (for
the SIP-MAC option). If a matching entry is found in the binding table and
the entry type is static IPv4 source guard binding, the packet will be
forwarded.
If DHCP snooping is enabled, IPv4 source guard will check the VLAN ID,
source IP address, port number, and source MAC address (for the SIP-MAC
option). If a matching entry is found in the binding table and the entry type
is static IPv4 source guard binding, or dynamic DHCP snooping binding, the
packet will be forwarded.
If IPv4 source guard is enabled on an interface for which IP source bindings
have not yet been configured (neither by static configuration in the IPv4
source guard binding table nor dynamically learned from DHCP snooping),
the switch will drop all IP traffic on that port, except for DHCP packets
allowed by DHCP snooping.
An entry with same MAC address and a different VLAN ID cannot be added to
the binding table.
Parameters
These parameters are displayed:
Port – Port identifier. (Range: 1-28)
Filter Type – Configures the switch to filter inbound traffic based source IP
address, or source IP address and corresponding MAC address. (Default: None)
Disabled – Disables IPv4 source guard filtering on the port.
SIP – Enables traffic filtering based on IPv4 addresses stored in the binding
table.