R2511-HP MSR Router Series Layer 3 - IP Services Command Reference(V5)

81
Usage guidelines
With this function enabled, DHCP snooping looks for a matching DHCP snooping entry for each
received DHCP-REQUEST message.
• If a match is found, DHCP snooping compares the entry with the message. If they are consistent,
DHCP snooping considers the DHCP-REQUEST message a valid lease renewal request and
forwards it to the DHCP server. If they are not consistent, DHCP snooping considers the message a
forged lease renewal request and discards it.
• If no match is found, DHCP snooping forwards the message to the DHCP server.
The following matrix shows the command in different views and hardware compatibility:
Hardware
Command in Layer 2
aggregate interface
vie
w
Command in Layer 2
Ethernet interface view
Command in WLAN-BSS
interface view
MSR900 No No Yes
MSR93X No No
Yes (Supported by the
JG512A, JG519A and
JG597A)
MSR20-1X No Yes Yes
MSR20 No Yes Yes
MSR30 Yes Yes Yes
MSR50 Yes Yes Yes
MSR1000 Yes Yes Yes
Examples
# Enable DHCP-REQUEST message check for DHCP snooping.
<Sysname> system-view
[Sysname] interface ethernet 1/1
[Sysname-Ethernet1/1] dhcp-snooping check request-message
dhcp-snooping information circuit-id format-type
Use dhcp-snooping information circuit-id format-type to configure the code type for the non-user-defined
circuit ID sub-option.
Use undo dhcp-snooping information circuit-id format-type to restore the default.
Syntax
dhcp-snooping information circuit-id format-type { ascii | hex }
undo dhcp-snooping information circuit-id format-type
Default
The code type for the circuit ID sub-option depends on the padding format of Option 82. Each field has
its own code type.
Views
Layer 2 Ethernet interface view, Layer 2 aggregate interface view, WLAN-BSS interface view