IP Configuration
IPv4 Management and Interfaces
Cisco Sx350, SG350X, SG350XG, Sx550X & SG550XG Series Managed Switches, Firmware Release 2.2.5.x
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STEP 4
Click
Apply
. The settings are written to the Running Configuration file.
DHCP Snooping Trusted Interfaces
Packets from untrusted ports/LAGs are checked against the DHCP Snooping Binding database
(see the
DHCP Snooping Binding Database
page).
By default, interfaces are trusted.
To designate an interface as untrusted:
STEP 1
Click
IP Configuration > IPv4 Management and Interfaces > DHCP Snooping/Relay >
DHCP Snooping Trusted Interfaces.
STEP 2
Select the interface and click
Edit
.
STEP 3
Select
Trusted Interface
(
Yes
or
No
).
STEP 4
Click
Apply
to save the settings to the Running Configuration file.
DHCP Snooping Binding Database
See
How the DHCP Snooping Binding Database is Built
for a description of how dynamic
entries are added to the DHCP Snooping Binding database.
Note the following points about maintenance of the DHCP Snooping Binding database:
•
The device does not update the DHCP Snooping Binding database when a station
moves to another interface.
•
If a port is down, the entries for that port are not deleted.
•
When DHCP Snooping is disabled for a VLAN, the binding entries that collected for
that VLAN are removed.
•
If the database is full, DHCP Snooping continue to forward packets but new entries are
not created. Note that if the IP source guard and/or ARP inspection features are active,
the clients that are not written in the DHCP Snooping Binding database are not be able
to connect to the network.
To add entries to the DHCP Snooping Binding database:
