Module 7: DHCPv4 Switching, Routing and Wireless Essentials v7.0 (SRWE) Cisco Networking Academy Program Switching, Routing and Wireless Essentials v7.0 (SRWE) Module 7: DHCPv4 ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Instructor Materials – Module 7 Planning Guide •This PowerPoint deck is divided in two parts: •Instructor Planning Guide •Information to help you become familiar with the module •Teaching aids •Instructor Class Presentation •Optional slides that you can use in the classroom •Begins on slide # 9 •Note: Remove the Planning Guide from this presentation before sharing with anyone. •For additional help and resources go to the Instructor Home Page and Course Resources for this course. You also can visit the professional development site on netacad.com, the official Cisco Networking Academy Facebook page, or Instructor Only FB group. ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential What to Expect in this Module §To facilitate learning, the following features within the GUI may be included in this module: § § • Feature Description Animations Expose learners to new skills and concepts. Videos Expose learners to new skills and concepts. Check Your Understanding(CYU) Per topic online quiz to help learners gauge content understanding. Interactive Activities A variety of formats to help learners gauge content understanding. Syntax Checker Small simulations that expose learners to Cisco command line to practice configuration skills. PT Activity Simulation and modeling activities designed to explore, acquire, reinforce, and expand skills. ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential What to Expect in this Module (Cont.) §To facilitate learning, the following features may be included in this module: Feature Description Hands-On Labs Labs designed for working with physical equipment. Class Activities These are found on the Instructor Resources page. Class Activities are designed to facilitate learning, class discussion, and collaboration. Module Quizzes Self-assessments that integrate concepts and skills learned throughout the series of topics presented in the module. Module Summary Briefly recaps module content. ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Check Your Understanding •Check Your Understanding activities are designed to let students quickly determine if they understand the content and can proceed, or if they need to review. •Check Your Understanding activities do not affect student grades. •There are no separate slides for these activities in the PPT. They are listed in the notes area of the slide that appears before these activities. • § ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module 7: Activities •What activities are associated with this module? • • • Page # Activity Type Activity Name Optional? 7.1.5 Check Your Understanding DHCPv4 Concepts Recommended 7.2.6 Syntax Checker Configure DHCPv4 Recommended 7.2.10 Packet Tracer Configure DHCPv4 Recommended 7.3.4 Syntax Checker Configure a Cisco Router as DHCP Client Recommended 7.4.1 Packet Tracer Implement DHCPv4 Recommended 7.4.2 Lab Implement DHCPv4 Recommended ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module 7: Best Practices •Prior to teaching Module 7, the instructor should: •Review the activities and assessments for this module. •Try to include as many questions as possible to keep students engaged during classroom presentation. •Topic 7.1 •Ask the students or have a class discussion •During the lease procedure, what is the reason for the client sending the DHCPREQUEST as a broadcast packet? •What Layer 2 protocol is peripherally involved during the DHCP process? • • • • § • • § § ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module 7: Best Practices (Cont.) •Topic 7.2 •Ask the students or have a class discussion •What scenarios do you think a router acting as a DHCPv4 server is the best course of action? •If the DHCPv4 server is not configured, does the dhcp service running on the router pose a security risk? •Topic 7.3 •Ask the students or have a class discussion •Based on your knowledge of DHCPv4 server configuration options, what options do you think most service providers make sure to provide to home router DHCPv4 clients? • • § § Switching, Routing and Wireless Essentials v7.0 (SRWE) Module 7: DHCPv4 Cisco Networking Academy Program Switching, Routing and Wireless Essentials v7.0 (SRWE) Module 7 – DHCPv4 ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Objectives •Module Title: DHCPv4 • •Module Objective: Implement DHCPv4 to operate across multiple LANs Topic Title Topic Objective DHCP4 Concepts Explain how DHCPv4 operates in a small- to medium-sized business network. Configure a Cisco IOS DHCP4 Server Configure a router as a DHCPv4 server. Configure a DHCP4 Client Configure a router as a DHCPv4 client. 7.0 – Introduction 7.0.2 – What will I learn to do in this module? ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7.1 DHCPv4 Concepts 7- DHCPv4 7.1 – DHCPv4 Concepts ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential DHCPv4 Concepts DHCPv4 Server and Client •Dynamic Host Configuration Protocol v4 (DHCPv4) assigns IPv4 addresses and other network configuration information dynamically. Because desktop clients typically make up the bulk of network nodes, DHCPv4 is an extremely useful and timesaving tool for network administrators. •A dedicated DHCPv4 server is scalable and relatively easy to manage. However, in a small branch or SOHO location, a Cisco router can be configured to provide DHCPv4 services without the need for a dedicated server. Cisco IOS software supports an optional, full-featured DHCPv4 server. •The DHCPv4 server dynamically assigns, or leases, an IPv4 address from a pool of addresses for a limited period of time chosen by the server, or until the client no longer needs the address. •Clients lease the information from the server for an administratively defined period. Administrators configure DHCPv4 servers to set the leases to time out at different intervals. The lease is typically anywhere from 24 hours to a week or more. When the lease expires, the client must ask for another address, although the client is typically reassigned the same address. • 7 – DHCPv4 7.1 – DHCPv4 Concepts 7.1.1 – DHCPv4 Server and Client ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential DHCPv4 Concepts DHCPv4 Operation •DHCPv4 works in a client/server mode. When a client communicates with a DHCPv4 server, the server assigns or leases an IPv4 address to that client. •The client connects to the network with that leased IPv4 address until the lease expires. The client must contact the DHCP server periodically to extend the lease. •This lease mechanism ensures that clients that move or power off do not keep addresses that they no longer need. •When a lease expires, the DHCP server returns the address to the pool where it can be reallocated as necessary. 7 – DHCPv4 7.1 – DHCPv4 Concepts 7.1.2 – DHCPv4 Operation ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential DHCPv4 Concepts Steps to Obtain a Lease When the client boots (or otherwise wants to join a network), it begins a four-step process to obtain a lease: 1.DHCP Discover (DHCPDISCOVER) 2.DHCP Offer (DHCPOFFER) 3.DHCP Request (DHCPREQUEST) 4.DHCP Acknowledgment (DHCPACK) 7 – DHCPv4 7.1 – DHCPv4 Concepts 7.1.3 – Steps to Obtain a Lease ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential DHCPv4 Concepts Steps to Renew a Lease Prior to lease expiration, the client begins a two-step process to renew the lease with the DHCPv4 server, as shown in the figure: 1. DHCP Request (DHCPREQUEST) Before the lease expires, the client sends a DHCPREQUEST message directly to the DHCPv4 server that originally offered the IPv4 address. If a DHCPACK is not received within a specified amount of time, the client broadcasts another DHCPREQUEST so that one of the other DHCPv4 servers can extend the lease. 2. DHCP Acknowledgment (DHCPACK) On receiving the DHCPREQUEST message, the server verifies the lease information by returning a DHCPACK. Note: These messages (primarily the DHCPOFFER and DHCPACK) can be sent as unicast or broadcast according to IETF RFC 2131. 7 – DHCPv4 7.1 – DHCPv4 Concepts 7.1.4 – Steps to Renew a Lease 7.1.5 – Check Your Understanding – DHCPv4 Concepts ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7.2 Configure a Cisco IOS DHCPv4 Server 7- DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Cisco IOS DHCPv4 Server •Now you have a basic understanding of how DHCPv4 works and how it can make your job a bit easier. A Cisco router running Cisco IOS software can be configured to act as a DHCPv4 server. The Cisco IOS DHCPv4 server assigns and manages IPv4 addresses from specified address pools within the router to DHCPv4 clients. 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.1 – Cisco IOS DHCPv4 Server ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Steps to Configure a Cisco IOS DHCPv4 Server •Use the following steps to configure a Cisco IOS DHCPv4 server: •Step 1. Exclude IPv4 addresses. A single address or a range of addresses can be excluded by specifying the low-address and high-address of the range. Excluded addresses should be those addresses that are assigned to routers, servers, printers, and other devices that have been, or will be, manually configured. You can also enter the command multiple times. The command is ip dhcp excluded-address low-address [high-address] •Step 2. Define a DHCPv4 pool name. The ip dhcp pool pool-name command creates a pool with the specified name and puts the router in DHCPv4 configuration mode, which is identified by the prompt Router(dhcp-config)#. • • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.2 – Steps to Configure a Cisco IOS DHCPv4 Server ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Steps to Configure a Cisco IOS DHCPv4 Server (Cont.) •Step 3. Configure the DHCPv4 pool. The address pool and default gateway router must be configured. Use the network statement to define the range of available addresses. Use the default-router command to define the default gateway router. These commands and other optional commands are shown in the table. • • Task IOS Command Define the address pool. network network-number [mask | / prefix-length] Define the default router or gateway. default-router address [ address2….address8] Define a DNS server. dns-server address [ address2…address8] Define the domain name. domain-name domain Define the duration of the DHCP lease. lease {days [hours [ minutes]] | infinite} Define the NetBIOS WINS server. netbios-name-server address [ address2…address8] 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.2 – Steps to Configure a Cisco IOS DHCPv4 Server (Cont.) ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Configuration Example 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.3 – Configuration Example ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server DHCPv4 Verification Use the commands in the table to verify that the Cisco IOS DHCPv4 server is operational. Command Description show running-config | section dhcp Displays the DHCPv4 commands configured on the router. show ip dhcp binding Displays a list of all IPv4 address to MAC address bindings provided by the DHCPv4 service. show ip dhcp server statistics Displays count information regarding the number of DHCPv4 messages that have been sent and received 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.4 – DHCPv4 Verification ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Verify DHCPv4 is Operational •Verify the DHCPv4 Configuration: As shown in the example, the show running-config | section dhcp command output displays the DHCPv4 commands configured on R1. The | section parameter displays only the commands associated with DHCPv4 configuration. • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.5 – Verify DHCPv4 is Operational ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Verify DHCPv4 is Operational (Cont.) •Verify DHCPv4 Bindings: As shown in the example, the operation of DHCPv4 can be verified using the show ip dhcp binding command. This command displays a list of all IPv4 address to MAC address bindings that have been provided by the DHCPv4 service. • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.5 – Verify DHCPv4 is Operational (Cont.) ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Verify DHCPv4 is Operational (Cont.) •Verify DHCPv4 Statistics: The output of the show ip dhcp server statistics is used to verify that messages are being received or sent by the router. This command displays count information regarding the number of DHCPv4 messages that have been sent and received. • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.5 – Verify DHCPv4 is Operational (Cont.) ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Verify DHCPv4 is Operational (Cont.) •Verify DHCPv4 Client Received IPv4 Addressing: The ipconfig /all command, when issued on PC1, displays the TCP/IP parameters, as shown in the example. Because PC1 was connected to the network segment 192.168.10.0/24, it automatically received a DNS suffix, IPv4 address, subnet mask, default gateway, and DNS server address from that pool. No DHCP-specific router interface configuration is required. If a PC is connected to a network segment that has a DHCPv4 pool available, the PC can obtain an IPv4 address from the appropriate pool automatically. • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.5 – Verify DHCPv4 is Operational (Cont.) 7.2.6 – Syntax Checker – Configure DHCPv4 ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Disable the Cisco IOS DHCPv4 Server •The DHCPv4 service is enabled by default. To disable the service, use the no service dhcp global configuration mode command. Use the service dhcp global configuration mode command to re-enable the DHCPv4 server process, as shown in the example. Enabling the service has no effect if the parameters are not configured. •Note: Clearing the DHCP bindings or stopping and restarting the DHCP service may result in duplicate IP addresses being temporarily assigned on the network. • • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.7 – Disable the Cisco IOS DHCPv4 Server ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server DHCPv4 Relay •In a complex hierarchical network, enterprise servers are usually located centrally. These servers may provide DHCP, DNS, TFTP, and FTP services for the network. Network clients are not typically on the same subnet as those servers. In order to locate the servers and receive services, clients often use broadcast messages. •In the figure, PC1 is attempting to acquire an IPv4 address from a DHCPv4 server using a broadcast message. In this scenario, R1 is not configured as a DHCPv4 server and does not forward the broadcast. Because the DHCPv4 server is located on a different network, PC1 cannot receive an IP address using DHCP. R1 must be configured to relay DHCPv4 messages to the DHCPv4 server. • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.8 – DHCPv4 Relay ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server DHCPv4 Relay (Cont.) •Configure R1 with the ip helper-address address interface configuration command. This will cause R1 to relay DHCPv4 broadcasts to the DHCPv4 server. As shown in the example, the interface on R1 receiving the broadcast from PC1 is configured to relay DHCPv4 address to the DHCPv4 server at 192.168.11.6. •When R1 has been configured as a DHCPv4 relay agent, it accepts broadcast requests for the DHCPv4 service and then forwards those requests as a unicast to the IPv4 address 192.168.11.6. The network administrator can use the show ip interface command to verify the configuration. 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.8 – DHCPv4 Relay (Cont.) ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Other Service Broadcasts Relayed •DHCPv4 is not the only service that the router can be configured to relay. By default, the ip helper-address command forwards the following eight UDP services: •Port 37: Time •Port 49: TACACS •Port 53: DNS •Port 67: DHCP/BOOTP server •Port 68: DHCP/BOOTP client •Port 69: TFTP •Port 137: NetBIOS name service •Port 138: NetBIOS datagram service • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.9 – Other Service Broadcasts Relayed ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Cisco IOS DHCPv4 Server Packet Tracer – Configure DHCPv4 •In this Packet Tracer Activity, you will complete the following objectives: •Part 1: Configure a Router as a DHCP Server •Part 2: Configure DHCP Relay •Part 3: Configure a Router as a DHCP Client •Part 4: Verify DHCP and Connectivity • 7 – DHCPv4 7.2 – Configure a Cisco IOS DHCPv4 Server 7.2.10 – Packet Tracer – Configure DHCPv4 ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7.3 Configure a DHCPv4 Client 7- DHCPv4 7.3 – Configure a DHCPv4 Client ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a DHCPv4 Client Cisco Router as a DHCPv4 Client •There are scenarios where you might have access to a DHCP server through your ISP. In these instances, you can configure a Cisco IOS router as a DHCPv4 client. •Sometimes, Cisco routers in a small office or home office (SOHO) and branch sites have to be configured as DHCPv4 clients in a similar manner to client computers. The method used depends on the ISP. However, in its simplest configuration, the Ethernet interface is used to connect to a cable or DSL modem. •To configure an Ethernet interface as a DHCP client, use the ip address dhcp interface configuration mode command. •In the figure, assume that an ISP has been configured to provide select customers with IP addresses from the 209.165.201.0/27 network range after the G0/0/1 interface is configured with the ip address dhcp command. • 7 – DHCPv4 7.3 – Configure a DHCPv4 Client 7.3.1 - Cisco Router as a DHCPv4 Client ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a DHCPv4 Client Configuration Example •To configure an Ethernet interface as a DHCP client, use the ip address dhcp interface configuration mode command, as shown in the example. This configuration assumes that the ISP has been configured to provide select customers with IPv4 addressing information. •The show ip interface g0/1 command confirms that the interface is up and that the address was allocated by a DHCPv4 server. 7 – DHCPv4 7.3 – Configure a DHCPv4 Client 7.3.2 – Configuration Example ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a DHCPv4 Client Home Router as a DHCPv4 Client •Home routers are typically already set to receive IPv4 addressing information automatically from the ISP. This is so that customers can easily set up the router and connect to the internet. •For example, the figure shows the default WAN setup page for a Packet Tracer wireless router. Notice that the internet connection type is set to Automatic Configuration - DHCP. This selection is used when the router is connected to a DSL or cable modem and acts as a DHCPv4 client, requesting an IPv4 address from the ISP. •Various manufacturers of home routers will have a similar setup. • 7 – DHCPv4 7.3 – Configure a DHCPv4 Client 7.3.3 – Home Router as a DHCPv4 Client 7.3.4 – Syntax Checker – Configure a Cisco IOS Router as DHCP Client ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7.4 Module Practice and Quiz 7- DHCPv4 7.4 – Module Practice and Quiz ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Practice and Quiz Packet Tracer – Implement DHCPv4 •In this Packet Tracer, you will complete the following objectives: •Part 1: Configure a Router as a DCHP Server •Part 2: Configure DCHP Relay •Part 3: configure a Router as a DCHP Client 7 – DHCPv4 7.4 – Module Practice and Quiz 7.4.1 – Packet Tracer – Implement DHCPv4 ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Practice and Quiz Lab – Implement DHCPv4 •In this lab, you will complete the following objectives: §Part 1: Build the Network and Configure Basic Device Settings §Part 2: Configure and Verify Two DHCPv4 Servers on R1 §Part 3: Configure and Verify a DHCP Relay on R2 § 7 – DHCPv4 7.4 – Module Practice and Quiz 7.4.2 – Lab – Implement DHCPv4 ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Practice and Quiz What Did I Learn In This Module? •The DHCPv4 server dynamically assigns, or leases, an IPv4 address to a client from a pool of addresses for a limited period of time chosen by the server, or until the client no longer needs the address. •The DHCPv4 lease process begins with the client sending message requesting the services of a DHCP server. If there is a DHCPv4 server that receives the message it will respond with an IPv4 address and possible other network configuration information. •The client must contact the DHCP server periodically to extend the lease. This lease mechanism ensures that clients that move or power off do not keep addresses that they no longer need. •When the client boots (or otherwise wants to join a network), it begins a four-step process to obtain a lease: DHCPDISCOVER, then DHCPOFFER, then DHCPREQUEST, and finally DHCPACK. Prior to lease expiration, the client begins a two-step process to renew the lease with the DHCPv4 server: DHCPREQUEST then DHCPACK. •A Cisco router running Cisco IOS software can be configured to act as a DHCPv4 server. •Use the following steps to configure a Cisco IOS DHCPv4 server: exclude IPv4 addresses, define a DHCPv4 pool name, and configure the DHCPv4 pool. •Verify your configuration using the show running-config | section dhcp, show ip dhcp binding, and show ip dhcp server statistics commands. •The DHCPv4 service is enabled, by default. To disable the service, use the no service dhcp global configuration mode command. 7 – DHCPv4 7.4 – Module Practice and Quiz 7.4.3 – What Did I Learn In This Module ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Practice and Quiz What Did I Learn In This Module? (Cont.) •Network clients are not typically on the same subnet as enterprise servers providing DHCP, DNS, TFTP, and FTP services for the network. In order to locate the servers and receive services, clients often use broadcast messages. The router must be configured to relay DHCPv4 messages to the DHCPv4 server. •The network administrator can configure the router with the ip helper-address address interface configuration command and use the show ip interface command to verify the configuration. •By default, the ip helper-address command forwards the following eight UDP services: •Port 37: Time •Port 49: TACACS •Port 53: DNS •Port 67: DHCP/BOOTP server •Port 68: DHCP/BOOTP client •Port 69: TFTP •Port 137: NetBIOS name service •Port 138: NetBIOS datagram service •To configure an Ethernet interface as a DHCP client, use the ip address dhcp interface configuration mode command. •Home routers are typically already set to receive IPv4 addressing information automatically from the ISP. The internet connection type is set to Automatic Configuration - DHCP. This selection is used when the router is connected to a DSL or cable modem and acts as a DHCPv4 client, requesting an IPv4 address from the ISP. 7 – DHCPv4 7.4 – Module Practice and Quiz 7.4.3 – What Did I Learn In This Module (Cont.) 7.4.4 – Module Quiz – DHCPv4 ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module 7: DHCPv4 New Terms and Commands •Dynamic Host Configuration Protocol (DHCP) •DHCP Discover (DHCPDISCOVER) •DHCP Offer (DHCPOFFER) •DHCP Request (DHCPREQUEST) •DHCP Acknowledgment (DHCPACK) •ip dhcp excluded-address low-address [high-address] •ip dhcp pool name •network network-number [mask | /prefix-length] •default-router address [address2 ... address8] •dns-server address [address2 ... address8] •domain-name domain •lease {days [hours [minutes]] | infinite} •netbios-name-server address [address2 ... address8] •show running-config | section dhcp •show ip dhcp binding •show ip dhcp server statistics •[no] service dhcp •ip helper-address address •ip address dhcp