Edge-Core ES4524M-PoE, Management Manual, Page: 139 / 560

Client Security
3-95
IP Source Guard
IP Source Guard is a security feature that filters IP traffic on network interfaces
based on manually configured entries in the IP Source Guard table, or dynamic
entries in the DHCP Snooping table when enabled (see “DHCP Snooping” on page
3-88). IP source guard can be used to prevent traffic attacks caused when a host
tries to use the IP address of a neighbor to access the network. This section
describes commands used to configure IP Source Guard.
IP Source Guard Port Configuration
IP Source Guard is used to filter traffic on an unsecure port which receives
messages from outside the network or firewall, and therefore may be subject to
traffic attacks caused by a host trying to use the IP address of a neighbor.
Command Usage
• Setting source guard mode to SIP (Source IP) or SIP-MAC (Source IP and MAC)
enables this function on the selected port. Use the SIP option to check the VLAN
ID, source IP address, and port number against all entries in the binding table. Use
the SIP-MAC option to check these same parameters, plus the source MAC
address. If no matching entry is found, the packet is dropped.
• When enabled, traffic is filtered based upon dynamic entries learned via DHCP
snooping (see “DHCP Snooping Configuration” on page 3-90), or static addresses
configured in the source guard binding table.
• If the 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.
• Filtering rules are implemented as follows:
- If the DHCP snooping is disabled (see page 3-90), IP 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 IP source guard binding, the packet will be forwarded.
- If the DHCP snooping is enabled, IP 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 IP source guard binding, or dynamic DHCP snooping binding, the packet
will be forwarded.
- If IP source guard if enabled on an interface for which IP source bindings have
not yet been configured (neither by static configuration in the IP source guard
binding table nor dynamically learned from DHCP snooping), the switch will drop
all IP traffic on that port, except for DHCP packets.
Command Attributes
• Filter Type – Configures the switch to filter inbound traffic based source IP
address, or source IP address and corresponding MAC address. (Default: None)
• None – Disables IP source guard filtering on the port.