Which of the following kinds of information are part of a DHCP server configuration?
This topic discusses on minimum DHCP server configuration, complete DHCP server configuration, extended DHCP server configuration. You can also use this topic for information on how to configure a router as a DHCP server, switch as a DHCP server, DHCP server on switches, and a device as a DHCP server. Show
DHCP Server Configuration OverviewA typical DHCP server configuration provides the following configuration settings for a particular subnet on a device ingress interface:
In addition, the DHCP server might assign a static address to at least one client on the subnet. Table 1 provides the settings and values for the sample DHCP server configuration. Table 1: Sample DHCP Server Configuration Settings
Minimum DHCP Local Server ConfigurationThe following sample output shows the minimum configuration you must use to configure an SRX300, SRX320, SRX340, SRX345, SRX550M, or SRX1500 device as a DHCP server. In this output, the server group is named mobileusers, and the DHCP local server is enabled on ingress interface ge-1/0/1.0 within the group. The address pool is named acmenetwork from low range of 192.168.1.10/24 to a high range of 192.168.1.20/24. [edit access] address-assignment { pool acmenetwork { family inet { network 192.168.1.0/24; range r1 { low 192.168.1.10; high 192.168.1.20; } } } } [edit system services] dhcp-local-server { group mobileusers { interface ge-1/0/1.0 } } [edit interfaces ge-1/0/1 unit 0] family { inet { address 192.168.1.1/24 } } Note: You can configure the DHCP local server in
a routing instance by using the This example shows the minimum configuration you need to use for the extended DHCP local server at group-level: [edit system services] dhcp-local-server { group group_one { interface ge-0/0/2.0; } } This example creates the server group named Note: If you delete the DHCP server configuration, DHCP server bindings might still remain. To ensure that DHCP bindings are removed, issue the This example shows the minimum configuration you need to use for the extended DHCP local server at group-level. If there is a dynamic profile configuration for interface
ge-0/0/2, you should add an interface in the [edit system services] dhcp-local-server { group group_one { interface ge-0/0/2.0; } } This example creates the server group named Example: Complete DHCP Server ConfigurationThis topic shows a complete DHCP server configuration.
Requirements
OverviewYou can configure a DHCP server only on an interface’s primary IP address. The primary address on an interface is the address that is used by default as the local address for broadcast and multicast packets sourced locally and sent out the interface. The following example shows statements at the ConfigurationTo configure the DHCP server, perform these tasks:
Configuring [item]Step-by-Step Procedure
Configure Legacy DHCP ServerStep-by-Step Procedure
Configure a Router as an Extended DHCP Local ServerYou can enable the router to function as an extended DHCP local server and configure the extended DHCP local server options on the router. The extended DHCP local server provides an IP address and other configuration information in response to a client request. The extended DHCP local server enhances traditional DHCP server operation in which the client address pool and client configuration information reside on the DHCP server. With the extended DHCP local server, the client address and configuration information reside in centralized address-assignment pools, which are managed independently of the DHCP local server and which can be shared by different client applications. The extended DHCP local server also supports advanced pool matching and the use of named address ranges. You can also configure the local server to use DHCP option 82 information in the client PDU to determine which named address range to use for a particular client. The client configuration information, which is configured in the address-assignment pool, includes user-defined options, such as boot server, grace period, and lease time. Configuring the DHCP environment that includes the extended DHCP local server requires two independent configuration operations, which you can complete in any order. In one operation, you configure the extended DHCP local server on the router and specify how the DHCP local server determines which address-assignment pool to use. In the other operation, you configure the address-assignment pools used by the DHCP local server. The address-assignment pools contain the IP addresses, named address ranges, and configuration information for DHCP clients. See IP Address Assignment Pool for details about creating and using address-assignment pools. Note: The extended DHCP local server and the address-assignment pools used by the server must be configured in the same logical system and routing instance. You cannot configure the extended DHCP local server and extended DHCP relay on the same interface. To configure the extended DHCP local server on the router, include the [edit system services] dhcp-local-server { authentication { password password-string; username-include { circuit-type; delimiter delimiter-character; domain-name domain-name-string; logical-system-name; mac-address; option-60; option-82 You can also include these statements at the following hierarchy levels:
In addition, you can configure tracing for DHCP local server operations by including the [edit system processes] traceoptions { file filename Configuring a Switch as a DHCP ServerA Dynamic Host Configuration Protocol (DHCP) server provides a framework to pass configuration information to client hosts on a TCP/IP network. A switch acting as a DHCP server can dynamically allocate IP addresses and other configuration parameters, minimizing the overhead that is required to add clients to the network. A DHCP configuration consists of two components—an optional reconfiguration of default settings on DHCP clients and the configuration of a DHCP server. This topic covers configuration of the switch as a local DHCP server using DHCP for IPv4 (DHCPv4). For information about DHCPv6 local server, see DHCPv6 Local Server Overview. This topic describes the following task: Configuring the Switch as a Local DHCP ServerTo configure a switch as a local DHCP server, you must configure a DHCP address pool and indicate IP addresses for the pool. The switch, operating as the DHCP server, dynamically distributes the IP addresses from this pool. The switch can dynamically assign additional configuration parameters, such as default gateway, to provide the client with information about the network. Multiple address pools can be configured for a DHCP server. DHCP maintains the state information about all configured pools. Clients are assigned addresses from pools with subnets that match the interface on which the DHCPDISCOVER packet sent by the client is received on the server. When more than one pool exists on the same interface, addresses are assigned on a rotating basis from all available pools. You must ensure that you do not assign addresses that are already in use in the network to the address pools. The DHCP server does not check whether the addresses are already in use in the network before it assigns them to clients.
Configuring a DHCP Server on SwitchesA Dynamic Host Configuration Protocol (DHCP) server can provide two valuable TCP/IP network services. DHCP can dynamically allocate IP parameters, such as an IP address, to clients and it can also deliver software upgrades to clients. A DHCP configuration consists of two components—an optional reconfiguration of default settings on DHCP clients and the configuration of a DHCP server. This topic covers configuration of the DHCP server. For information about reconfiguring a DHCP client, see Configuring a DHCP Client. You can configure either of two versions of a DHCP server on a switch— the extended server version or the legacy server version. We recommend that you configure the extended server unless you need to keep your DHCP server configuration backward-compatible with the legacy server version. This topic includes the following tasks: Configuring an Extended DHCP Server on a SwitchTo configure an extended DHCP server, you must configure a DHCP pool, indicate IP addresses for the pool, and create a server group. Additional configurations are optional. Do not assign addresses that are already in use in the network to address pools. The extended DHCP server does not check whether addresses are already in use before it assigns them to clients.
Example: Configuring a Security Device as a DHCP ServerThis example shows how to configure the device as a DHCP server. For information on how to configure JDHCP in a routing instance, see How to configure JDHCP in a routing instance.
RequirementsBefore you begin:
OverviewIn this example, you configure the device as a DHCP server. You specify the IP address pool as 192.168.2.0/24 and from a low range of 192.168.2.2 to a high range of 192.168.2.254. You set the maximum-lease-time to 2,419,200. Then you specify the DNS server IP address as 192.168.10.2. Warning: Starting with Junos OS Release 15.1X49-D60 and Junos OS Release 17.3R1, the legacy DHCPD (DHCP daemon) configuration on all SRX Series devices is being deprecated. and only the new JDHCP CLI is supported. When you upgrade to Junos OS Release 15.1X49-D60 and later releases on a device that already has the DHCPD configuration, the following warning messages are displayed: WARNING: The DHCP configuration command used will be deprecated in future Junos releases. WARNING: Please see documentation for updated commands. ConfigurationProcedure
CLI Quick ConfigurationTo quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the commands into the CLI at the set interfaces ge-0/0/2 unit 0 family inet address 192.168.2.1/24 set system services dhcp-local-server group g1 interface ge-0/0/2.0 set access address-assignment pool p1 family inet network 192.168.2.0/24 set access address-assignment pool p1 family inet range r1 low 192.168.2.2 set access address-assignment pool p1 family inet range r1 high 192.168.2.254 set access address-assignment pool p1 family inet dhcp-attributes maximum-lease-time 2419200 set access address-assignment pool p1 family inet dhcp-attributes name-server 192.168.10.2 GUI Quick ConfigurationStep-by-Step Procedure To configure the device as a DHCP server, specify the DHCP pool information, server information, lease time, and option information:
Step-by-Step ProcedureThe following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode in the CLI User Guide. To configure the device as a DHCP server:
Results
[edit]
user@host#
If you are done configuring the device, enter VerificationConfirm that the configuration is working properly.
Verifying the DHCP Binding Database
PurposeVerify that the DHCP binding database reflects the DHCP server configuration. ActionFrom operational mode, enter these commands:
These commands produce following sample output: user@host> show dhcp server binding IP Address Hardware Address Type Lease expires at 30.1.1.20 00:12:1e:a9:7b:81 dynamic 2007-05-11 11:14:43 PDT user@host> show dhcp server binding address detail IP address 192.0.2.2 Hardware address 00:a0:12:00:13:02 Pool 192.0.2.0/24 Interface fe-0/0/0, relayed by 192.0.2.200 Lease information: Type DHCP Obtained at 2004-05-02 13:01:42 PDT Expires at 2004-05-03 13:01:42 PDT State active DHCP options: Name: name-server, Value: { 6.6.6.6, 6.6.6.7 } Name: domain-name, Value: mydomain.tld Code: 32, Type: ip-address, Value: 192.0.2.33 Verifying DHCP Server Operation
PurposeVerify that the DHCP server operation has been configured. ActionFrom operational mode, enter the following command:
user@host> show dhcp server statistics Packets dropped: Total 0 Messages received: BOOTREQUEST 45 DHCPDECLINE 0 DHCPDISCOVER 1 DHCPINFORM 39 DHCPRELEASE 0 DHCPREQUEST 5 DHCPLEASEQUERY 0 DHCPBULKLEASEQUERY 0 Messages sent: BOOTREPLY 6 DHCPOFFER 1 DHCPACK 3 DHCPNAK 2 DHCPFORCERENEW 0 DHCPLEASEUNASSIGNED 0 DHCPLEASEUNKNOWN 0 DHCPLEASEACTIVE 0 DHCPLEASEQUERYDONE 0 Release History Table 15.1X49-D60 Starting with Junos OS Release 15.1X49-D60 and Junos OS Release 17.3R1, the legacy DHCPD (DHCP daemon) configuration on all SRX Series devices is being deprecated. and only the new JDHCP CLI is supported. Which of the following is a kind of information are a part of DHCP server configuration?The DHCP server stores the configuration information in a database that includes: Valid TCP/IP configuration parameters for all clients on the network. Valid IP addresses, maintained in a pool for assignment to clients, as well as excluded addresses. Reserved IP addresses associated with particular DHCP clients.
What three key information is provided to a host by DHCP?The DHCP service brings three key values: 1) Operation tasks are reduced: the network administrator no longer needs to manually configure each client before it can use the network 2) The IP addressing plan is optimized: addresses no longer being used are freed up and made available to new clients connecting 3) User ...
What are the different types of DHCP configuration?Basically, the following three types of IP address allocations are used by DHCP when assigning IP addresses to DHCP clients:. Automatic. The automatic lease is used to assign permanent IP addresses to hosts. ... . Dynamic. The dynamic lease is the most commonly used type. ... . Manual.. What are the 4 types of DHCP packets?The complete DHCP exchange involves four types of packets: Discover, for your computer to locate the DHCP server; Offer, for the server to offer an IP address; Request, for your computer to ask for an of- fered address; and Ack, for the server to grant the address lease.
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