Security
IP Source Guard
372 Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version)
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STEP 1 Click Security > IP Source Guard > Interface Settings.
STEP 2 Select port/LAG from the Filter field and click Go. The ports/LAGs on this unit are
displayed along with the following:
•IP Source Guard —Indicates whether IP Source Guard is enabled on the
port.
•DHCP Snooping Trusted Interface—Indicates whether this is a DHCP trusted
interface.
STEP 3 Select the port/LAG and click Edit. Select Enable in the IP Source Guard field to
enable IP Source Guard on the interface.
STEP 4 Click Apply to copy the setting to the Running Configuration file.
Binding Database
IP Source Guard uses the DHCP Snooping Binding database to check packets
from untrusted ports. If the device attempts to write too many entries to the DHCP
Snooping Binding database, the excessive entries are maintained in an inactive
status. Entries are deleted when their lease time expires and so inactive entries
may be made active.
See DHCPv4 Snooping/Relay.
NOTE The Binding Database page only displays the entries in the DHCP Snooping
Binding database defined on IP-Source-Guard-enabled ports.
To view the DHCP Snooping Binding database and see TCAM usage, set Insert
Inactive:
STEP 1 Click Security > IP Source Guard > Binding Database.
STEP 2 The DHCP Snooping Binding database uses TCAM resources for managing the
database. Complete the Insert Inactive field to select how frequently the device
should attempt to activate inactive entries. It has the following options:
•Retry Frequency—The frequency with which the TCAM resources are
checked.
•Never-Never try to reactivate inactive addresses.
STEP 3 Click Apply to save the above changes to the Running Configuration and/or Retry
Now to check TCAM resources.