Question

Difficulty: EasyIP Addressing Services

A system administrator is configuring core IP services across multiple subnets in an enterprise network. Which TWO of the following configurations are required to allow hosts on remote subnets to automatically acquire IPv4 addresses and resolve domain names to IPv4 addresses? (Select TWO)

  1. Configuring a DHCP relay agent (IP helper) on the default gateway interface of each client subnetAnswer
  2. Creating DNS A records on the domain name server for internal hostnamesAnswer
  3. C
    Deploying an independent DHCP server on every physical switch to avoid routing DHCP traffic
  4. D
    Creating DNS PTR records to handle forward domain-name-to-IP-address resolution
  5. E
    Opening firewall UDP port 53 for DHCP client leases and UDP port 67 for DNS hostname lookups

Answer

The necessary configurations are deploying a DHCP relay agent (IP helper) on local router interfaces to forward DHCP broadcasts across subnets, and creating DNS A records to resolve hostnames to IPv4 addresses.
A DHCP relay agent (IP helper) allows clients on remote subnets to reach a central DHCP server by converting local broadcast requests into unicast traffic. Additionally, DNS A records perform forward address resolution from domain names to IPv4 addresses.

Step-by-Step Solution

1
Determine the service required to pass DHCP requests across router boundaries.
Identify that routers block broadcast packets, requiring a DHCP relay agent (IP helper) on the gateway interface to forward client lease requests to a remote DHCP server.
DHCP discover messages are sent as Layer 2 broadcasts, which cannot traverse subnets without a relay.
2
Identify the appropriate DNS record type for resolving hostnames to IPv4 addresses.
Select DNS A records as the proper mechanism for forward IPv4 resolution.
A records specifically map fully qualified domain names (FQDNs) to 32-bit IPv4 addresses.

Key Concept

IP Addressing Services (DHCP Relay and DNS Record Types)
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