DHCP Relay
BOOTP/DHCP Relay extends Bootstrap Protocol (BOOTP) and Dynamic Host Configuration Protocol (DHCP) operation across multiple hops in a routed network. In standard BOOTP, all interfaces on a LAN are loaded from a single configuration server on the LAN. BOOTP Relay allows configuration requests to be forwarded to and serviced from configuration servers located outside the single LAN.
BOOTP/DHCP Relay offers the following advantages over standard BOOTP/DHCP:
- You can provide redundancy by configuring an interface on the Check Point system to relay client configuration requests to multiple servers. With this setup, configuration requests are relayed to all the listed servers simultaneously.
- You can provide load balancing by configuring multiple interfaces on the Check Point system to relay client configuration requests to different servers.
- It allows you to centrally manage client configuration across multiple LANs. This is particularly useful in large enterprise environments.
The Gaia implementation of BOOTP Relay is compliant with RFC 951, RFC 1542, and RFC 2131. BOOTP Relay supports Ethernet and IEEE 802 LANs by using canonical MAC byte ordering, that is, clients that specify Bootp htype=1: 802.3 and FDDI.
When an interface configured for BOOTP Relay receives a boot request, it forwards the request to all the servers in its server list. It does this after waiting a specified length of time to see if a local server answers the boot request. If a primary IP is specified, it stamps the request with that address, otherwise it stamps the request with the lowest numeric IP address specified for the interface.
Configuring DHCP Relay - WebUI
Use the WebUI to enable BOOTP/DHCP Relay on each interface. If the interface is enabled for relay, you can set up a number of servers to which to forward BOOTP/DHCP requests.
To enable BOOTP/DHCP relay on an Interface
- Open the page of the WebUI.
- Click .
The window opens.
- Select an on which you want to enable BOOTP/DHCP.
- Optional: Enter values for one or more of these parameters:
- Define the IPv4 address of each relay to which you want to forward BOOTP/DHCP requests. For each relay:
- Click
- In the window, enter the of the relay
- Click .
- Click .
To disable BOOTP/DHCP relay on an interface
- Open the page of the WebUI.
- Select an interface.
- Click .
BOOTP/DHCP Parameters
Parameter
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Description
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The IP address to use as the BOOTP/DHCP router address. If you enter an IP address, all BOOTP/DHCP requests received on the interface are stamped with this gateway address. This can be useful on interfaces with multiple IP addresses (aliases).
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The minimum time to wait (in seconds) for a local configuration server to answer the boot request before forwarding the request through the interface. This delay provides an opportunity for a local configuration server to reply before attempting to relay to a remote server. Set the wait time to a sufficient length to allow the local configuration server to respond before the request is forwarded. If no local server is present, set the time to zero (0).
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The IPv4 address of the BOOTP/DHCP configuration server to which to forward BOOTP/DHCP requests. You can configure relay to multiple configuration servers independently on each interface. Configuring different servers on different interfaces provides load balancing, while configuring multiple servers on a single interface provides redundancy. The server IPv4 address cannot be an address belonging to the local machine.
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BOOTP Interfaces
Use these commands to configure BOOTP properties for specific interfaces.
set bootp interface <if_name>
primary ip_address wait‑time <0‑65535> on
relay‑to ip_address <on | off>
off
Arguments
Parameter
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Description
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primary ip_address wait‑time <0‑65535> on
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The ip_address to stamp as the gateway address on all BOOTP requests.
The wait‑time value is the minimum seconds to wait before forwarding a bootp request. A client‑generated bootp request includes the elapsed time after the client began to boot. The bootp relay does not forward the request until the indicated elapsed time at least equals the specified wait time. This delay lets a local configuration server reply, before it relays to a remote server.
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relay‑to ip_address <on | off>
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The server to which BOOTP requests are forwarded. You can specify more than one server.
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off
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Disables BOOTP on the specified interface.
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BOOTP Show Commands
Use this group of commands to monitor and troubleshoot the BOOTP implementation.
show bootp
interfaces
interface if_name
stats
stats receive
stats request
stats reply
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