Configuring DHCP Snooping on Allied Telesis

In this article, I will give an example of configuring DHCP Snooping on Allied Telesis switches

Let’s go to the configuration mode:

configure

Let’s enable DHCP Snooping globally:

ip dhcp snooping

Let’s configure a trusted UPLINK port (so that DHCP server responses can come from it):

interface ethernet g1
ip dhcp snooping trust

Enable DHCP Snooping on the required VLAN:

ip dhcp snooping vlan 983

Done, exit the configuration mode and look at the DHCP table:

exit
show ip dhcp snooping binding

Let’s save the configuration:

copy running-config startup-config

I will give an example of canceling the previously entered commands:

configure
no ip dhcp snooping vlan 983
interface ethernet g1
no ip dhcp snooping trust
exit
no ip dhcp snooping

I will give an example of adding an entry manually (where 983 is the VLAN number):

ip dhcp snooping binding 0000.1111.2222 983 192.168.5.5 ethernet e5

To allow packets with option-82 from untrusted ports use the command:

ip dhcp snooping information option allowed-untrusted
no ip dhcp snooping information option allowed-untrusted

Checking the MAC address in a packet with the client’s hardware MAC address:

ip dhcp snooping verify
no ip dhcp snooping verify

Change the update time of the file with the DHCP bindings table (range 600 – 86400, default 1200):

ip dhcp snooping database update-freq SECONDS
no ip dhcp snooping database update-freq

Clearing DHCP Snooping Bindings Table:

clear ip dhcp snooping database

See also my articles:
Configuring Allied Telesis AT-8000S
Configuring Switchport Protected on Allied Telesis

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