Netgear M5300-28G-POE+ (GSM7228PSv1h2) - 12-Port Managed Gigabit Switch Ratgeber Für Administratoren
DHCP L2 Relay and L3 Relay
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Managed Switches
DHCP L2 Relay
DHCP relay agents eliminate the need to have a DHCP server on each physical network.
Relay agents populate the giaddr field and also append the Relay Agent Information
option to the DHCP messages. DHCP servers use this option for IP addresses and other
parameter assignment policies. These DHCP relay agents are typically IP routing-aware
devices and are referred to as Layer 3 relay agents.
Relay agents populate the giaddr field and also append the Relay Agent Information
option to the DHCP messages. DHCP servers use this option for IP addresses and other
parameter assignment policies. These DHCP relay agents are typically IP routing-aware
devices and are referred to as Layer 3 relay agents.
In some network configurations, Layer 2 devices can append the relay agent Information
option as they are closer to the end hosts.
option as they are closer to the end hosts.
DHCP Server #1
Host #1
Host #2
Layer 2 Switch #1
1/0/4
1/0/5
1/0/6
Figure 60. DHCP L2 Relay
These Layer 2 devices typically operate only as bridges for the network and might not have
an IPv4 address on the network. Lacking a valid IPv4 source address, they cannot relay
packets directly to a DHCP server on another network. These Layer 2 devices append the
Relay agent information option and broadcast the DHCP message. This section provides
information about where a Layer 2 relay agent fits in and how it is used.
an IPv4 address on the network. Lacking a valid IPv4 source address, they cannot relay
packets directly to a DHCP server on another network. These Layer 2 devices append the
Relay agent information option and broadcast the DHCP message. This section provides
information about where a Layer 2 relay agent fits in and how it is used.
CLI: Enable DHCP L2 Relay
1.
Enter the following commands:
(Netgear Switch)#vlan database
(Netgear Switch)(Vlan)#vlan 200
(Netgear Switch)(Vlan)#exit