General Security Measures

4-139

4

IP Source Guard Commands

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
Commands" on page 4-131). 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

This command configures the switch to filter inbound traffic based source IP
address, or source IP address and corresponding MAC address. Use the no form to
disable this function.
Syntax
ip source-guard {sip | sip-mac}
no ip source-guard
sip - Filters traffic based on IP addresses stored in the binding table.
sip-mac - Filters traffic based on IP addresses and corresponding MAC
addresses stored in the binding table.
Default Setting
Disabled
Command Mode
Interface Configuration (Ethernet)
Command Usage
Source guard is used to filter traffic on an insecure port which receives
messages from outside the network or fire wall, and therefore may be subject
to traffic attacks caused by a host trying to use the IP address of a neighbor.
Setting source guard mode to “sip” or “sip-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. Use
the no source guard command to disable this function on the selected port.
Table 4-43 IP Source Guard Commands
Command Function Mode Page
ip source-guard Configures the switch to filter inbound traffic based on source IP
address, or source IP address and corresponding MAC address
IC 4-139
ip source-guard
binding
Adds a static address to the source-guard binding table GC 4-141
show ip
source-guard
Shows whether source guard is enabled or disabled on each
interface
PE 4-142
show ip
source-guard
binding
Shows the source guard binding table PE 4-142