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Zorluk: OrtaDHCP Server, Client, and Relay Agent Operation and Configuration

An enterprise network engineer is configuring a Cisco IOS router (R1) to forward DHCP requests from client hosts located on subnet 10.50.1.0/2410.50.1.0/24 to a centralized DHCP server with IPv4 address 172.16.10.25172.16.10.25. Client hosts connect directly to R1 via interface GigabitEthernet0/0/1 (10.50.1.1/2410.50.1.1/24), while interface GigabitEthernet0/0/0 (172.16.1.1/24172.16.1.1/24) routes traffic toward the DHCP server network. Which configuration command must be applied to ensure R1 properly relays client DHCP broadcast requests to the server?

  1. Apply the `ip helper-address 172.16.10.25` command under the incoming client gateway interface GigabitEthernet0/0/1 configuration mode.Cevap
  2. B
    Apply the `ip helper-address 172.16.10.25` command under the egress interface GigabitEthernet0/0/0 configuration mode.
  3. C
    Configure `ip helper-address 10.50.1.1` globally on R1 to enable DHCP relay across all router interfaces.
  4. D
    Configure an `ip dhcp pool` on interface GigabitEthernet0/0/1 with a `default-router` setting of 172.16.10.25.

Cevap

Apply the command `ip helper-address 172.16.10.25` on interface GigabitEthernet0/0/1.
To function as a DHCP relay agent, a Cisco router interface receiving client broadcast requests must be configured with `ip helper-address <server-ip>`. Applying this command to the client-facing gateway interface (GigabitEthernet0/0/1) enables the router to listen for UDP port 67 broadcast traffic, encapsulate it as unicast, insert its gateway IP address (`giaddr`), and send it directly to the designated DHCP server (172.16.10.25172.16.10.25).

Adım Adım Çözüm

1
Identify the ingress interface receiving client DHCP broadcasts
Interface GigabitEthernet0/0/1 receives the initial DHCPDISCOVER broadcast packets from client hosts on subnet 10.50.1.0/2410.50.1.0/24.
DHCP broadcast traffic (255.255.255.255255.255.255.255) is dropped by routers by default unless intercepted at the incoming gateway interface.
2
Determine the correct command syntax and placement for DHCP relay agent functionality
Executing `ip helper-address 172.16.10.25` within `config-if` mode on GigabitEthernet0/0/1 configures R1 to forward DHCP broadcasts as unicast packets to the target server IP address.
The router sets the `giaddr` (gateway IP address) field in the DHCP packet header to 10.50.1.110.50.1.1, allowing the remote server to select the correct IP pool.

Anahtar Kavram

DHCP Relay Agent Interface Placement and Operation
Tahmini Süre:1m 15s
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DHCP Server, Client, and Relay Agent Operation and Configuration

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