Motorola EX-3524, Cli Reference Manual

Page: 252 / 617

Chapter 8
| General Security Measures
IP Source Guard
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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 ip
source guard command to disable this function on the selected port.
◆
When enabled, traffic is filtered based upon dynamic entries learned via DHCP
snooping, or static addresses configured in the source guard binding table.
◆
Table entries include a MAC address, IP address, lease time, entry type (Static-IP-
SG-Binding, Dynamic-DHCP-Binding, VLAN identifier, and port identifier.
◆
Static addresses entered in the source guard binding table with the ip source-
guard binding command ( page 250 ) are automatically configured with an
infinite lease time. Dynamic entries learned via DHCP snooping are configured
by the DHCP server itself.
◆
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 DHCP snooping is disabled (see page 242 ), IP source guard will check the
VLAN ID, source IP address, port number, and source MAC address (for the