Configuring Cisco Router as DHCP Client

200-301 By islever Editorial Last updated

Configure and verify DHCP client and relay Explain the role of DHCP and DNS within the network

Short answer

A The ip address dhcp command configures an interface to obtain an IP address from a DHCP server, thereby enabling the router to function as a DHCP client.

Question

Which command enables a router to become a DHCP client?
  1. ip address dhcp Correct Answer
  2. ip dhcp client
  3. ip helper-address
  4. ip dhcp pool

Key Takeaways

The main trap is confusing 'ip dhcp client' (a parameter prefix) with 'ip address dhcp' (the activation command). Only the latter triggers the DHCP discovery process on an interface.

Learn how to configure a Cisco router as a DHCP client using the ip address dhcp command. This guide clarifies common misconceptions about ip dhcp client options versus actual client activation.

Common mistake: Candidates often choose 'ip dhcp client' thinking it enables the client. However, it requires subcommands and does not activate the client service on its own.

Expert Analysis

The question asks for the command that enables a router to become a DHCP client. To understand why Option A is correct and others are not, we must look at how Cisco IOS handles DHCP on interfaces.

Option A (ip address dhcp): This is the decisive command. When applied to an interface, it instructs the router to request an IP address from a DHCP server. Without this command, the interface will not attempt to acquire an address via DHCP, regardless of other settings. Community comments confirm this by stating that "ip address dhcp" is the command that makes the client send DHCP DISCOVER messages. One commenter noted that while ip dhcp client commands exist, they are optional parameters; the core action of enabling the client behavior is performed by ip address dhcp.

Option B (ip dhcp client): As highlighted in the comments, ip dhcp client is not a standalone command that enables the client mode. It is a parent keyword followed by specific subcommands like client-id, class-id, or lease. Therefore, typing just ip dhcp client without a subcommand does nothing to enable DHCP on the interface.

Option C (ip helper-address): This command is used to configure a router as a DHCP Relay Agent, forwarding broadcast requests to a remote DHCP server. It allows the router to assist clients on other networks but does not make the router itself a client seeking an address.

Option D (ip dhcp pool): This command is used in global configuration mode to define a pool of addresses for the router to act as a DHCP Server. It is completely unrelated to the client role.

Therefore, the qualifier "enables a router to become a DHCP client" specifically targets the interface-level activation of the client protocol, which is exclusively achieved by ip address dhcp.

Official Reference

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-4/dhcp-12-4-book/config-dhcp-client.html

This link opens the official vendor documentation in a new tab.

Exam Strategy

When asked how to 'enable' a service on an interface, look for the primary operational command rather than parameter definitions. In Cisco IOS, activation commands often start with the feature name followed by the mode (e.g., 'ip address dhcp'). Distinguish between server configurations (pools, helper-address) and client configurations (ip address dhcp) by identifying whether the router is providing or requesting resources.

Frequently Asked Questions

What is the difference between ip address dhcp and ip helper-address?

ip address dhcp makes the router's interface a DHCP client that requests an IP. ip helper-address makes the router a relay agent that forwards DHCP broadcasts to a server.

Do I need to use ip dhcp client commands to enable DHCP?

No. ip dhcp client commands are optional parameters like client-id or lease time. The essential command to activate DHCP on an interface is ip address dhcp.

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Community Votes

A
100%

100% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 36 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 30 of 36

  1. akhuseyinoglu 👍 23
    Correct Answer : A
  2. Daimen 👍 13
    A is the right answer. ip dhcp address makes the router become a dhcp client. ip dhcp client is needed to enable some parameters which makes the router(dhcp client) function properly.
  3. Niharikakaringula 👍 6
    answer is A Client(config)#interface FastEthernet 0/0 Client(config-if)#ip address dhcp Client(config-if)#no shutdown https://networklessons.com/cisco/ccna-200-301/dhcp-client-on-cisco-ios
  4. SanchezEldorado 👍 5
    I was really confused for a bit, but the answer is A. The snippet in the previous comment is only part of the statement. You ONLY need to configure "ip dhcp client" commands before "ip add dhcp" IF you want them to be enabled right away. It doesn't mean that you actually NEED to use "ip DHCP client" commands. In otherwords, you don't NEED option values to enable DHCP on the interface. "The ip dhcp client commands are checked only when an IP address is acquired from DHCP. If any of the ip dhcp client commands are entered after an IP address has been acquired from DHCP, it will not take effect until the next time the router acquires an IP address from DHCP. This means that the new configuration will take effect only after either the ip address dhcp command or the release dhcp and renew dhcpEXECcommandshave been configured." https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-4/dhcp-12-4-book/config-dhcp-client.html
  5. TeeItUp 👍 5
    Correct Answer: B "You must configure the ip dhcp client commands before entering the ip address dhcp command on an interface to ensure that the DHCPDISCOVER messages that are generated contain the correct option values."
Show 25 more comments
  1. JimGrayham 👍 5
    A. ip address dhcp. CCNA 200-301: Official Cert Guide Vol. 1 P.197 Chapter 6: Configuring Basic Switch Management.
  2. boghota 👍 4
    I can confirm this. ISR4331 Router in Cisco Packet Tracer shows: Router(config)#ip dhcp ? excluded-address Prevent DHCP from assigning certain addresses pool Configure DHCP address pools relay DHCP relay agent parameters Router(config)#int g0/0/0 Router(config-if)#ip ? access-group Specify access control for packets address Set the IP address of an interface authentication authentication subcommands flow NetFlow Related commands hello-interval Configures IP-EIGRP hello interval helper-address Specify a destination address for UDP broadcasts mtu Set IP Maximum Transmission Unit nat NAT interface commands ospf OSPF interface commands proxy-arp Enable proxy ARP split-horizon Perform split horizon summary-address Perform address summarization Router(config-if)#ip address ? A.B.C.D IP address dhcp IP Address negotiated via DHCP Router(config-if)#ip address dhcp ? <cr>
  3. g_money 👍 4
    Correct Answer is A. Direct from Cisco website. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/15-mt/dhcp-15-mt-book/config-dhcp-client.html
  4. FlipperDP 👍 4
    A because all ip dhcp client cmd are optional. ip address dhcp is required
  5. DavidL 👍 4
    Answer A. In packet tracer it has no ip dhcp client command.
  6. Mountie 👍 3
    Before You Begin You must configure the ip dhcp client commands before entering the ip address dhcp command on an interface to ensure that the DHCPDISCOVER messages that are generated contain the correct option values. The ip dhcp client commands are checked only when an IP address is acquired from DHCP. If any of the ip dhcp client commands are entered after an IP address has been acquired from DHCP, it will not take effect until the next time the router acquires an IP address from DHCP. This means that the new configuration will take effect only after either the ip address dhcp command or the release dhcp and renew dhcpEXECcommandshave been configured. according to your link, ip dhcp client must be confugured before ip address dhcp to be able to configured.
  7. ariesccna 👍 3
    B is the correct https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-4/dhcp-12-4-book/config-dhcp-client.html#GUID-75502973-D32F-4438-A79D-7569BA87534A SUMMARY STEPS 1. enable 2. configure terminal 3. interface type number 4. ip dhcp client client-id {interface-name| ascii string| hex string} 5. ip dhcp client class-id {string| hex string} 6. ip dhcp client lease days [hours][minutes] 7. ip dhcp client hostname host-name 8. [no] ip dhcp client request option-name 9. ip address dhcp
  8. GodUsopp 👍 3
    IP DHCP CLIENT is not a full command it has many options such as (config-if)# ip dhcp client class-id my-class-id or (config-if)# ip dhcp client lease 2 or (config-if)# ip dhcp client hostname router1 or (config-if)# no ip dhcp client request tftp-server-address these are examples of the full commands for the ip dhcp client and all of them are optional commands. Source https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-4/dhcp-12-4-book/config-dhcp-client.html
  9. altiit 👍 3
    Correct Answer is A, Use the ip address dhcp command to obtain IP address information for the configured interface. ip dhcp client client-id {interface-name| ascii string| hex string} ip dhcp client class-id {string| hex string} ip dhcp client lease days [hours][minutes] ip dhcp client hostname host-name [no] ip dhcp client request option-name ip address dhcp Note: There is no command ip dhcp client without client-ID, class-ID, Hostname, request and lease.
  10. SanchezEldorado 👍 3
    The ip dhcp client commands are optional, not required. Look in the detailed steps in the link you posted. It shows optional. All you need is ip address dhcp to enable DHCP. See if you can get a DHCP address on an interface in a lab with just ip dhcp client commands. You can't.
  11. dendotes 👍 3
    I also think A is the correct answer here. IF being a DHCP client is what we are looking for, then "ip address dhcp" will make a it a client since it will ask an IP address on the DHCP server.
  12. ponder 👍 3
    A is correct simply because B isn't a valid command as stated.
  13. KingKeelo1 👍 3
    Correct answer is indeed A
  14. kimi7 👍 2
    from the cisco page https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-4/dhcp-12-4-book/config-dhcp-client.html On the DHCP server, the configuration is as follows: ip dhcp pool 1 network 10.1.1.0 255.255.255.0 lease 1 6 On the DHCP client, the configuration is as follows on interface E2: interface Ethernet2 ip address dhcp so how A is not the right answer i dont know...al the other options are set with ip address client...something but just to enable it to take ip its ip address dhcp
  15. icca17 👍 2
    Correct is A! Configuring the DHCP Client Cisco devices running Cisco software include the Dynamic Host Configuration Protocol (DHCP) server and relay agent software, which are enabled by default. Your device can act as both the DHCP client and the DHCP server. Use the ip address dhcp command to obtain IP address information for the configured interface. SUMMARY STEPS 1. enable 2. configure terminal 3. interface type number 4. ip address dhcp 5. end 6. debug dhcp detail 7. debug ip dhcp server packets
  16. Jpmuir 👍 2
    Cisco routers running Cisco IOS software include DHCP server and relay agent software, which are enabled by default. Your router can act as both the DHCP client and DHCP server. Use the ip address dhcp command to obtain IP address information for the configured interface.
  17. sojCCIE 👍 2
    Option A feels correct when configuring router's physical or loopback interface to obtain ip addr automatically via DHCP.Either of these can become the Router's ID on the network.please confirm.
  18. karemAbdullah 👍 2
    to configure the interface Gi0/0 on the router as a DHCP client. This is how this is done: R1(config)#int Gi0/0 R1(config-if)#ip address dhcp A is the correct answer
  19. diamcle 👍 2
    ip address dhcp is for Cisco IOS Release 15M&T ip dhcp client is for Cisco IOS Release 12.4 So, I thinh the question needs to be more specific.
  20. devildog 👍 2
    Correct answer is A straight from the cisco site.
  21. knister 👍 2
    Agree, this is the answer that makes more sense
  22. Ebenezer 👍 2
    This answer is wrong. The correct answer is A.
  23. Araz 👍 2
    A is a right answer
  24. SharonANita 👍 2
    ip address ---A
  25. GrigTech 👍 1
    Before You Begin You must configure the ip dhcp client commands before entering the ip address dhcp command on an interface to ensure that the DHCPDISCOVER messages that are generated contain the correct option values. The ip dhcp client commands are checked only when an IP address is acquired from DHCP. If any of the ip dhcp client commands are entered after an IP address has been acquired from DHCP, it will not take effect until the next time the router acquires an IP address from DHCP. This means that the new configuration will take effect only after either the ip address dhcp command or the release dhcp and renew dhcpEXECcommandshave been configured.

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