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DGS-3400 Series Layer 2 Gigabit Ethernet Managed Switch CLI Manual
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DGS-3450:admin# show address_binding
Command: show address_binding
Trap/Log
: Enabled
DHCP Snoop(IPv4) : Disabled
DHCP Snoop(IPv6) : Enabled
ND Snoop
: Disabled
DGS-3450:admin#
To show the IMPB ports:
DGS-3450:admin#show address_binding ports
Command: show address_binding ports
Port IPv4
IPv6 Mode Zero IP DHCP Packet Stop Learning
State State Threshold/Mode
-------- --------
-------- ---- --------- ----------- --------------
1 Loose Enabled
ARP Allow
Forward
100/Stop
2 Strict Enabled ARP Not Allow Not Forward
200/Normal
3 Disabled
Enabled ACL Not Allow Not Forward 200/Normal
4 Strict
Disabled ARP Not Allow Not Forward 200/Normal
5 Disabled
Disabled ACL Not Allow Not Forward 200/Normal
6 Strict
Disabled ARP Not Allow Not Forward 200/Normal
7 Disabled
Disabled ACL Not Allow Not Forward 200/Normal
8 Strict
Disabled ARP Not Allow Not Forward 200/Normal
9 Disabled
Disabled ACL Not Allow Not Forward 200/Normal
10 Strict
Disabled ARP Not Allow Not Forward 200/Normal
11 Disabled
Disabled ACL Not Allow Not Forward 200/Normal
12 Strict
Disabled ARP Not Allow Not Forward 200/Normal
DGS-3450:admin#
enable address_binding dhcp_snoop
Purpose
Used to enable DHCP snooping mode.
Syntax
enable address_binding dhcp_snoop {[ipv6 | all]}
Description
By default, DHCP snooping is disabled.
If a user enables DHCP sSnooping mode, all ports which have IMPB disabled will become
server ports. (The switch will learn the IP addresses through server ports (by using DHCP
Offer and DHCP ACK packets).
Note that the DHCP discover packet cannot be passed thru the user ports if the allow_zeroip
function is disabled on the port.
The auto-learned IMPB entry will be mapped to a specific source port based on the MAC
address learning function. This entry will be created as an ACL-mode binding entry for this
specific port. Each entry is associated with a lease time. When the lease time has expires,
the expired entry will be removed from the port. The auto-learned binding entry can be
moved from one port to another port if the DHCP snooping function has learned that the MAC
address has moved to a different port.
If a situation occurs where a binding entry learned by DHCP snooping conflicts with a
statically configured entry. The binding relation has conflicted. For example, if IP A is binded
to MAC X with a static configuration and suppose that the binding entry learned by DHCP
snooping is that IP A is bound to MAC Y, and then it is conflict. When the DHCP snooping
learned entry binds with the static configured entry, and the DHCP snooping learned entry
will not be created.
In a situation where the same IMPB pair has been statically configured, the auto-learned
entry will not be created. In a situation where the learned information is consistent with the