D-Link DES-3028 User Manual - Dhcp/bootp Relay

DES-3028 DES-3028P DES-3052 DES-3052P Layer 2 Fast Ethernet Managed Switch 

DHCP/BOOTP Relay 

To enable and configure DHCP/BOOTP Relay Global Settings on the Switch, click Administration > DHCP/BOOTP Relay>: 

DHCP/BOOTP Relay Global Settings 

Figure 6- 6.  DHCP/ BOOTP Relay Global Settings window 

The following fields can be set: 

Parameter 

                Description 

30

BOOTP Relay State  

This field can be toggled between Enabled and Disabled using the pull-down menu. It is 

used to enable or disable the DHCP/BOOTP Relay service on the Switch. The default is 

Disabled 

BOOTP Relay Hops 

Count Limit (1-16)  

This field allows an entry between 1 and 16 to define the maximum number of router hops 

DHCP/BOOTP messages can be forwarded across. The default hop count is 4. 

BOOTP Relay Time 

Threshold (0-65535) 

Allows an entry between 0 and 65535 seconds, and defines the maximum time limit for 

routing a DHCP/BOOTP packet. If a value of 0 is entered, the Switch will not process the 

value in the seconds field of the BOOTP or DHCP packet. If a non-zero value is entered, 

the Switch will use that value, along with the hop count to determine whether to forward a 

given BOOTP or DHCP packet. 

DHCP Relay Agent 

Information Option 82 

State 

This field can be toggled between Enabled and Disabled using the pull-down menu. It is 

used to enable or disable the DHCP Agent Information Option 82 on the Switch. The default 

is Disabled. 

Enabled – When this field is toggled to Enabled the relay agent will insert and remove 

DHCP relay information (option 82 field) in messages between DHCP servers and clients. 

When the relay agent receives the DHCP request, it adds the option 82 information, and the 

IP address of the relay agent (if the relay agent is configured), to the packet. Once the 

option 82 information has been added to the packet it is sent on to the DHCP server. When 

the DHCP server receives the packet, if the server is capable of option 82, it can implement 

policies like restricting the number of IP addresses that can be assigned to a single remote 

ID or circuit ID. Then the DHCP server echoes the option 82 field in the DHCP reply. The 

DHCP server unicasts the reply to the back to the relay agent if the request was relayed to 

the server by the relay agent. The switch verifies that it originally inserted the option 82 

data. Finally, the relay agent removes the option 82 field and forwards the packet to the 

switch port that connects to the DHCP client that sent the DHCP request. 

Disabled - If the field is toggled to Disabled the relay agent will not insert and remove DHCP 

relay information (option 82 field) in messages between DHCP servers and clients, and the 

check and policy settings will have no effect. 

DHCP Relay Agent 

Information Option 82 

This field can be toggled between Enabled and Disabled using the pull-down menu. It is 

used to enable or disable the Switches ability to check the validity of the packet’s option 82