A10E/A28E/A28F Configuration Guide
When the A10E/A28E receives a DHCP reply packet, delete the field and forward to
DHCP client if the packet does not contain Option field; forward packets directly if the
packet does not contain Option field.
3.6.2 Preparing for configurations
Scenario
DHCP Snooping is a security feature of DHCP, being used to guarantee DHCP client gets IP
address from legal DHCP server and record corresponding relationship between DHCP client
IP and MAC address.
Option field of DHCP packet records location of DHCP client. Administrator can locate
DHCP client through Option field and control client security and accounting. Device
configured with DHCP Snooping and Option can perform related process according to Option
field existence status in packet.
Prerequisite
DHCP Snooping is exclusive to DHCP Client, or DHCP Replay. Namely, you cannot
configure DHCP Relay on the device configured with DHCP Client, or DHCP Snooping.
3.6.3 Default configurations of DHCP Snooping
The default configuration of DHCP Snooping is as below.
Global DHCP Snooping status
Interface DHCP Snooping status
Interface trust/untrust status
DHCP Snooping in support of Option 82
3.6.4 Configuring DHCP Snooping
Generally, make sure that the A10E/A28E interface connected to DHCP server is in trust state,
while interface connected to user is in distrust state.
If enabling DHCP Snooping without configuring DHCP Snooping supporting Option function,
the A10E/A28E will do nothing to Option fields in the packets. For packets without Option
fields, the A10E/A28E still does not do insertion operation.
By default, the DHCP Snooping function of all interfaces is enabled, but only when global
DHCP Snooping is enabled, the interface DHCP Snooping can take effect.
Configure DHCP Snooping over IPv4 on the A10E/A28E as below.
Enter global configuration mode.
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