C H A P T E R 3

DHCP

Note - This chapter applies to the Sun Network 10GbE Switch 72p product only. DHCP is not supported on the Sun Blade 6000 Ethernet Switched NEM 24p 10GbE, so do not use any of the procedures in this chapter for that product.

DHCP allows dynamic configuration of a host computer. When a DHCP client is turned on, it initially does not have an IP address assigned to it. It issues a broadcast message to any DCHP servers that are on the network. An exchange takes place during which the DHCP server assigns an IP address to the client and tells the client certain key network configuration parameters.

Many ISPs require that their customers use a DHCP client, so the ISP may dynamically assign IP addresses and control other network settings. Another use is for laptop computers connected to more than one network. For example, when a laptop is connected to a network in the office and at home, the laptop need not be manually reconfigured for use in the two different networks. Instead, with a DHCP server on both the office network and the home network and with a DHCP Client in the laptop, this can be achieved easily.

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3.1 DHCP Commands

The list of CLI commands for the configuration of DHCP is as follows:

#### DHCP Client

- debug ip dhcp client

- release

- renew

- show ip dhcp client stats

#### DHCP Relay

- service dhcp-relay

- ip dhcp server

- ip helper-address

- ip dhcp relay information option

- ip dhcp relay circuit-id

- ip dhcp relay remote-id

- debug ip dhcp relay

- show ip dhcp relay information

- show dhcp server

#### DHCP Server

- service dhcp-server

- service dhcp

- ip dhcp pool

- ip dhcp next-server

- ip dhcp bootfile

- bootfile config-file

- ip dhcp

- ip dhcp option

- network

- excluded-address

- ip dhcp excluded-address

- domain-name

- dns-server

- netbios-name-server

- netbios-node-type

- default-router

- option

- lease

- utilization threshold

- host hardware-type

- debug ip dhcp server

- show ip dhcp server information

- show ip dhcp server pools

- show ip dhcp server binding

- show ip dhcp server statistics

##

3.2 DHCP Client

Details for DHCP Client commands.

### 3.2.1 `debug ip dhcp client`

Sets the debug level for tracing the DHCP client module. The `no` form of the command disables the debug level for the DHCP client.

    debug ip dhcp client {all | event | packets | errors | bind}

    no debug ip dhcp client {all | event | packets | errors | bind}

Syntax Description | all - All trace messages. event - Trace management messages. packets - Packets related messages. errors - Trace error code debug messages. bind - Trace bind messages.
Mode | Privileged EXEC
Defaults | Debugging is disabled.
Example | SEFOS# debug ip dhcp client all

#### Related Commands

- show ip dhcp client stats - Displays the DHCP client statistics information

### 3.2.2 `release`

Immediately releases the DHCP lease on the interface specified.

    release dhcp [{vlan 1-4094 | interface-type interface-id}]

Syntax Description | vlan - VLAN identifier. interface-type - Interface type. interface-id - Interface identifier.
Mode | Privileged EXEC
Defaults | Disabled.
Example | SEFOS# renew dhcp vlan 1
Notes | VLAN interface must have an IP address assigned by the DHCP server. If the router interface was not assigned an IP address by the DHCP server, the renew DHCP command fails and displays the following error message: `Interface does not have a DHCP originated address`

#### Related Commands

- ip address - Configures the current VLAN interface to dynamically acquire an IP address from the DHCP server

- show ip dhcp client stats - Displays the DHCP client statistics information

- show ip interface - Displays the IP interface configuration

### 3.2.3 `renew`

Immediately renews the DHCP lease for the interface specified.

    renew dhcp [{vlan 1-4094 | interface-type interface-id}]

Syntax Description | vlan - VLAN identifier. interface-type - Interface type. interface-id - Interface identifier.
Mode | Privileged EXEC
Defaults | Disabled.
Example | SEFOS# renew dhcp vlan 1
Notes | VLAN interface must have an IP address assigned by the DHCP server. If the router interface was not assigned an IP address by the DHCP. Server, the renew DHCP command fails and displays the following error message: `Interface does not have a DHCP originated address`

#### Related Commands

- ip address - Configures the current VLAN interface to dynamically acquire an IP address from the DHCP server

- show ip dhcp client stats - Displays the DHCP client statistics information

- show ip interface - Displays the IP interface configuration

### 3.2.4 `show ip dhcp client stats`

Displays the DHCP client statistics.

    show ip dhcp client stats

Mode | Privileged EXEC
Example | SEFOS# show ip dhcp client stats Dhcp Client Statistics -------------------------- Interface : vlan3 Client IP Address : 0.0.0.0 Client Lease Time : 0 Client Remain Lease Time : 0 Message Statistics ------------------ DHCP DISCOVER : 1 DHCP REQUEST : 0 DHCP DECLINE : 0 DHCP RELEASE : 0 DHCP INFORM : 0 DHCP OFFER : 1

#### Related Commands

- ip address - Configures the current VLAN interface to dynamically acquire an IP address from the DHCP server

- release - Releases the DHCP lease on the interface specified

- renew - Renews the DHCP lease for the interface specified

##

3.3 DHCP Relay

Details for DHCP Relay commands.

### 3.3.1 `service dhcp-relay`

Enables the DHCP relay agent in the switch. The `no` form of the command disables the DHCP relay agent. The relay agent becomes active once it is enabled.

    service dhcp-relay

    no service dhcp-relay

Mode | Global Configuration
Defaults | Disabled.
Example | SEFOS(config)# service dhcp-relay
Notes | The DHCP server should be disabled before enabling the DHCP relay.

#### Related Commands

- `no` service dhcp-server / `no` service dhcp - Disables the DHCP server

- show dhcp server - Displays the DHCP server information

- show ip dhcp relay information - Displays the DHCP relay information

### 3.3.2 `ip dhcp server`

Sets the IP address of the DHCP server. The relay agent now starts forwarding the packets (that is, UDP broadcasts including BOOTP) from the client to the specified DHCP server. This command allows to add more than one DHCP server. The `no` form of the command deletes the DHCP server IP address.

    ip dhcp server ip-address

    no ip dhcp server ip-address

Syntax Description | ip-address - IP address of the server to which the packets are to be forwarded.
Mode | Global Configuration
Defaults | The IP address is 0.0.0.0 and the status of the DHCP relay servers only is disabled.
Example | SEFOS(config)# ip dhcp server 12.0.0.1
Notes | The relay agent will start forwarding the packets from the client to a specific DHCP server only when the relay agent is in the enabled state.

#### Related Commands

- show ip dhcp relay information - Displays the DHCP relay information

- show dhcp server - Displays the DHCP server information

### 3.3.3 `ip helper-address`

Sets the IP address of the DHCP server. The relay agent now starts forwarding the packets (that is, UDP broadcasts including BOOTP) from the client to the specified DHCP server. This command allows to add more than one DHCP server.

This command operates similar to the command ip dhcp server. This command also explicitly enables the DHCP relay and disables the DHCP server.

    ip helper-address ip-address

Syntax Description | ip-address - IP address of the server to which the packets are to be forwarded.
Mode | Interface Configuration
Defaults | The IP address is 0.0.0.0 and the status of only the DHCP Relay Servers is disabled.
Example | SEFOS(config-if)# ip helper-address 12.0.0.1
Notes | The relay agent will start forwarding the packets from the client to a specific DHCP server only when the relay agent is in the enabled state.

#### Related Commands

- show ip dhcp relay information - Displays the DHCP relay information

- show dhcp server - Displays the DHCP server information

### 3.3.4 `ip dhcp relay information option`

Enables the relay agent to perform any processing related to relay agent Information Options. The agent will insert DHCP relay information in DHCP request messages forwarded to the DHCP server, when the relay information option is enabled. The `no` form of this command disables the insertion of relay information.

    ip dhcp relay information option

    no ip dhcp relay information option

Mode | Global Configuration Can also be executed in the VLAN Interface Configuration for a code base with industry-standard commands.
Defaults | Relay information option is disabled.
Example | SEFOS(config)# ip dhcp relay information option SEFOS(config-if)# ip dhcp relay information option
Notes | Only when enabled, the relay agent does any processing related to relay agent Information Options - like inserting the necessary options while relaying a packet from a client to a server and examining or stripping of options when relaying a packet from a server to a client.

#### Related Commands

- show ip dhcp relay information - Displays the DHCP relay information

- show dhcp server - Displays the DHCP server information

### 3.3.5 `ip dhcp relay circuit-id`

Configures circuit-id value for this interface. The `no` form of the command deletes the circuit-id configuration for this interface.

    ip dhcp relay circuit-id 1-2147483647

    no ip dhcp relay circuit-id

Syntax Description | circuit-id - Value ranges from 1 to 2147483647.
Mode | Interface Configuration
Example | SEFOS(config-if)# ip dhcp relay circuit-id 1

### 3.3.6 `ip dhcp relay remote-id`

Configures the `remote-id` value for this interface. The `no` form of the command deletes the `remote-id` configuration.

    ip dhcp relay remote-id name

    no ip dhcp relay remote-id

Syntax Description | remote-id - Name of the remote identifier.
Mode | Interface Configuration
Example | SEFOS(config-if)# ip dhcp relay remote-id Aricent

### 3.3.7 `debug ip dhcp relay`

Enables the debug level for tracing the DHCP relay module. The `no` form of the command disables the debug level for tracing the DHCP relay module.

    debug ip dhcp relay {all | errors}

    no debug ip dhcp relay {all | errors}

Syntax Description | all - All trace messages. errors - Trace error code debug messages.
Mode | Privileged EXEC
Defaults | Debugging is disabled.
Example | SEFOS# debug ip dhcp relay all

#### Related Commands

- show ip dhcp relay information - Displays the DHCP relay information

- show dhcp server - Displays the DHCP server information

### 3.3.8 `show ip dhcp relay information`

Displays the DHCP relay information.

    show ip dhcp relay information [vlan 4-1094]

Mode | Privileged EXEC
Example | SEFOS# show ip dhcp relay information Dhcp Relay : Disabled Dhcp Relay Servers only : Disabled DHCP server : 0.0.0.0 Dhcp Relay RAI option : Disabled Debug Level : 0x1 No of Packets inserted RAI option : 0 No of Packets inserted circuit ID suboption : 0 No of Packets inserted remote ID suboption : 0 No of Packets inserted subnet mask suboption : 0 No of Packets dropped : 0 No of Packets which did not inserted RAI option : 0

#### Related Commands

- service dhcp-relay - Enables the DHCP relay agent in the switch

- ip dhcp server / ip helper-address - Sets the IP address of the DHCP server

- ip dhcp relay information option - Enables the relay agent to perform any processing related to relay agent Information Options

### 3.3.9 `show dhcp server`

Displays the DHCP server information.

    show dhcp server

Mode | Privileged EXEC
Example | SEFOS# show dhcp server DHCP server: 40.0.0.4

#### Related Commands

- service dhcp-relay - Enables the DHCP relay agent in the switch

- ip dhcp server / ip helper-address - Sets the IP address of the DHCP server

- ip dhcp relay information option - Enables the relay agent to perform any processing related to relay agent Information Options

##

3.4 DHCP Server

Details of DHCP Server commands.

### 3.4.1 `service dhcp-server`

Enables the DHCP server. The `no` form of this command disables the DHCP server.

    service dhcp-server

    no service dhcp-server

Mode | Global Configuration
Defaults | Disabled.
Example | SEFOS(config)# service dhcp-server
Notes | DHCP relay must be disabled before enabling the DHCP server.

#### Related Commands

- `no` service dhcp-relay - Disables the DHCP Relay

- show ip dhcp server information - Displays the DHCP server information

### 3.4.2 `service dhcp`

Enables the DHCP server. The `no` form of this command disables the DHCP server. This command operates similar to the command service dhcp-server.

    service dhcp

    no service dhcp

Mode | Global Configuration
Defaults | DHCP server is disabled.
Example | SEFOS(config)# service dhcp
Notes | DHCP Relay must be disabled before enabling the DHCP server.

#### Related Commands

- `no` service dhcp-relay - Disables the DHCP Relay

- show ip dhcp server information - Displays the DHCP server information

### 3.4.3 `ip dhcp pool`

Creates a DHCP server address pool and places the user in the DHCP pool configuration mode. The no form of the command deletes the DHCP server address pool.

    ip dhcp pool index_1-2147483647

    no ip dhcp pool index_1-2147483647

Syntax Description | index_1-2147483647 - Pool number.
Mode | Global Configuration
Defaults | Address pools are not created by default.
Example | SEFOS(config)# ip dhcp pool 1
Notes | On execution of this command, the configuration mode changes to DHCP pool configuration mode, identified by the`(config-dhcp)#` prompt. In this mode, the administrator can configure pool parameters.

#### Related Commands

- network - Sets the network number and mask in DHCP server configuration parameters

- excluded-address / ip dhcp excluded-address - Creates an excluded pool to prevent DHCP from assigning certain addresses

- domain-name - Sets the domain name in the DHCP server configuration parameters

- dns-server - Specifies the IP address of a DNS server

- netbios-name-server - Sets the NetBIOS (WINS) name servers in the DHCP server configuration parameters

- netbios-node-type - Sets the NetBios node type in the DHCP server configuration parameters

- default-router - Sets the default router in the DHCP server configuration parameters

- option - Sets the pool specific DHCP server option

- lease - Sets the lease period

- host hardware-type - Specifies the hardware address of a Dynamic Host Configuration Protocol (DHCP) client

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

### 3.4.4 `ip dhcp next-server`

Sets the next boot server in the DHCP server configuration parameters. The no form of this command deletes the next boot server from the DHCP server configuration parameters.

    ip dhcp next-server ip-address

    no ip dhcp next-server

Syntax Description | ip-address - IP address of the server (TFTP server).
Mode | Global Configuration
Example | SEFOS(config)# ip dhcp next-server 12.0.0.1

#### Related Commands

- service dhcp-server - Enables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server statistics - Displays the DHCP server statistics

### 3.4.5 `ip dhcp bootfile`

Defines the name of the boot image file that the DHCP client should download during auto install process. The DHCP server passes this file name to the DHCP client. The `no` form of this command deletes the specified boot file name and assigns the value of boot file name as None (that is, no file is set as boot image file).

    ip dhcp bootfile 63

    no ip dhcp bootfile

Syntax Description | bootfile - Name of the boot image file that should be downloaded by the DHCP client.
Mode | Global Configuration
Defaults | None (Null terminated string).
Example | SEFOS(config)# ip dhcp bootfile boot.img

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

### 3.4.6 `bootfile config-file`

Defines the name of the boot image file that the DHCP client should download during auto install process. The DHCP server passes this file name to the DHCP client. The `no` form of this command deletes the specified boot file name and assigns the value of boot file name as None (that is, no file is set as boot image file).

This command operates similar to the command ip dhcp bootfile.

    bootfile config-file 63

    no bootfile config-file

Syntax Description | bootfile - Name of the boot image file that should be downloaded by the DHCP client.
Mode | Global Configuration
Defaults | None (Null terminated string).
Example | SEFOS(config)# bootfile config-file boot.img

#### Related Commands

- show ip dhcp server information - Displays the DHCP server information

### 3.4.7 `ip dhcp`

Sets the DHCP server parameters such as enabling ICMP echo mechanism or offer-reuse timeout. The `no` form of this command is used to set the DHCP server parameters like disabling ICMP echo mechanism or server offer-reuse to its default value or removing a bind entry from the server binding table.

    ip dhcp {ping packets [count_0-10] | server offer-reuse timeout_1-120}

    no ip dhcp {ping packets | server offer-reuse | binding ip-address

Syntax Description | ping packets - Enable icmp echo prior to assigning a pool address. The no form of this command option prevents the server from pinging pool addresses. The count feature of this parameter allows to set the number of ping packets to be sent from the DHCP server to the pool address before assigning the address to a requesting client. The pinging of pool addresses is disabled, if the count value is set as 0. server offer-reuse - The amount of time the DHCP server entity would wait for the DHCP REQUEST from the client before reusing the offer. binding - The binding option if specified deletes the specified address from binding.
Mode | Global Configuration Mode
Defaults | server offer-reuse - 10
Example | SEFOS(config)# ip dhcp ping packets
Notes | The DHCP server pings a pool address before assigning the address to a requesting client. If the ping is unanswered, the DHCP server assumes (with a high probability) that the address is not in use and assigns the address to the requesting client.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server statistics - Displays the DHCP server statistics

### 3.4.8 `ip dhcp option`

Sets the DHCP server options.

    ip dhcp option code_1-2147483647 {ascii string | hex hex-string | ip address}

    no ip dhcp option code_1-2147483647

Syntax Description | code - Option code. ascii - ASCII string. hex - Hexadecimal string. ip - IP address.
Mode | Global Configuration
Example | SEFOS(config)# ip dhcp option 19 hex d
Notes | RFC 2132 provides details about option code to option name mapping and the option length information. The following is the list of supported/configurable DHCP options with their corresponding option length values. Options 19, 20, 27, 29, 30, 31, 34, 36, 39, 46 must have length 1. Options 12, 14, 15, 17, 18, 40, 43, 47, 64, 66, 67 must have length >=1. Option 16 must have minimum length 4 and the value for this option must be an IP address and Option 25 can have a length of 2 and 2*n. Option 68 must have length 4 and the value for this option must be an IP address. Options 1-11, 41, 42, 44, 45, 48, 49, 65, 69, 70-76 must have a length of 4. Value for these options must be an IP address. Options 21, 33 must have minimum length as 8 and 8*n. Options 0, 255, 50-60 are non-configurable options.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server pools - Displays the DHCP server pools

- ip dhcp relay information option - Sets the pool specific DHCP server option

### 3.4.9 `network`

Sets the network IP address and mask in DHCP server configuration parameters. The `no` form of the command deletes the network IP address and mask from DHCP server configuration.

    network network-IP [ {mask | / prefix-length_1-31}] [end ip]

    no network

Syntax Description | network-IP - Network IP address of the DHCP pool. mask - Subnet mask of the DHCP pool. prefix-length_1-31 - The number of bits that comprise the address prefix. Prefix is an alternative way of specifying the network mask of the client. The prefix length must be preceded by a forward slash (/). end ip- End IP address of the pool.
Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config)# network 20.0.0.0 255.0.0.0 20.0.0.100
Notes | This command is valid for DHCP sub network address pools only.

#### Related Commands

- ip dhcp pool - Creates a DHCP server address pool and places the user in the DHCP pool configuration mode

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

### 3.4.10 `excluded-address`

Creates an excluded pool to prevent DHCP server from assigning certain addresses to DHCP clients. The `no` form of the command deletes the excluded pool.

    excluded-address low-address high-address

    no excluded-address low-address high-address

Syntax Description | low-address - The excluded IP address, or first IP address in an excluded address range. high-address - The last IP address in the excluded address range.
Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config)# excluded-address 20.0.0.20 20.0.0.30
Notes | The DHCP server assumes that all pool addresses may be assigned to clients. This command is used to exclude a single IP address or a range of IP addresses. Subnet pool should have been created before creating an excluded pool. This excluded pool should be within the range of the created subnet pool. For example, the excluded pool 20.0.0.20 - 20.0.0.30 created using this command is within the already created subnet pool 20.0.0.0 - 20.0.0.100.

#### Related Commands

- ip dhcp pool - Creates a DHCP server address pool and places the user in the DHCP pool configuration mode

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

### 3.4.11 `ip dhcp excluded-address`

Creates an excluded pool to prevent DHCP server from assigning certain addresses to DHCP clients. The no form of the command deletes the excluded pool.

This command operates similar to the command excluded-address. This command is used to exclude a single IP address or a range of IP addresses.

    ip dhcp excluded-address low-address high-address

    no ip dhcp excluded-address low-address high-address

Syntax Description | low-address - The excluded IP address, or first IP address in an excluded address range. high-address - The last IP address in the excluded address range.
Mode | Global Configuration
Example | SEFOS(config)# ip dhcp excluded-address 20.0.0.20 20.0.0.30
Notes | The DHCP server assumes that all pool addresses may be assigned to clients. Subnet pool should have been created before creating an excluded pool. This excluded pool should be within the range of the created subnet pool. For example, the excluded pool 20.0.0.20 - 20.0.0.30 created using this command is within the already created subnet pool 20.0.0.0 - 20.0.0.100.

#### Related Commands

- ip dhcp pool - Creates a DHCP server address pool and places the user in the DHCP pool configuration mode

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

### 3.4.12 `domain-name`

Sets the domain name in the DHCP server configuration parameters. The no form of the command deletes the domain name from the DHCP server configuration parameters.

    domain-name domain_63

    no domain-name

Syntax Description | domain_63 - Client’s domain name string.
Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config)# domain-name aricent
Notes | The configuration of this command will take effect only after configuring the network address pool using network command.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

- network - Configures the network IP address of the DHCP Address Pool

### 3.4.13 `dns-server`

Specifies the IP address of a DNS server that is available to a DHCP client. The `no` form of the command deletes the DNS server from the DHCP server configuration parameters.

    dns-server ip-address

    no dns-server

Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config)# dns-server 20.0.0.1
Notes | If DNS IP servers are not configured for a DHCP client, the client cannot correlate host names to IP addresses. The configuration of this command will take effect only after configuring the network address pool using network command.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

- network - Configures the network IP address of the DHCP Address Pool

### 3.4.14 `netbios-name-server`

Sets the NetBIOS (WINS) name servers in the DHCP server configuration parameters. The no form of the command deletes the NetBIOS name server from the DHCP configuration parameters.

    netbios-name-server ip-address

    no netbios-name-server

Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config)# netbios-name-server 20.0.0.3
Notes | The configuration of this command will take effect only after configuring the network address pool using network command.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

- network - Configures the network IP address of the DHCP Address Pool

### 3.4.15 `netbios-node-type`

Sets the NetBIOS node type in the DHCP server configuration parameters. The `no` form of this command is used to delete the NetBios node type from the DHCP server configuration parameters.

The NetBIOS node type for Microsoft DHCP clients can be one of the four settings: broadcast, peer-to-peer, mixed, or hybrid.

    netbios-node-type {0-FF | b-node | h-node | m-node | p-node}

    no netbios-node-type

Syntax Description | 0-FF - Node type value. b-node - Broadcast node. h-node - Hybrid node. m-node - Mixed node. p-node - Peer-to-peer node.
Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config)# netbios-node-type h-node
Notes | The recommended type is hybrid node The configuration of this command will take effect only after configuring the network address pool using network command

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

- network - Configures the network IP address of the DHCP Address Pool

### 3.4.16 `default-router`

Sets the default router in the DHCP server configuration parameters. The `no` form of the command deletes the default router from the DHCP server configuration parameters.

    default-router ip-address

    no default-router

Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config)# default-router 10.23.2.99
Notes | The configuration of this command will take effect only after configuring the network address pool using network command.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

- network - Configures the network IP address of the DHCP Address Pool

### 3.4.17 `option`

Sets the pool specific DHCP server option. The `no` form of the command deletes the pool specific DHCP server option.

    option code_1-2147483647 {ascii string | hex hex-string | ip address}

    no option code_1-2147483647

Syntax Description | code - Option code. ascii - ASCII string. hex - Hexadecimal string. ip - IP address.
Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config) # option 19 hex f
Notes | RFC 2132 provides details about option code to option name mapping and the option length information. The following is the list of supported/configurable DHCP options with their corresponding option length values. Options 19, 20, 27, 29, 30, 31, 34, 36, 39, 46 must have length 1. Options 12, 14, 15, 17, 18, 40, 43, 47, 64, 66, 67 must have length>=1. Option 16 must have minimum length 4 and the value for this option must be an IP address and Option 25 can have a length of 2 and 2*n. Option 68 must have length 4 and the value for this option must be an IP address. Options 1-11, 41, 42, 44, 45, 48, 49, 65, 69, 70-76 must have a length of 4. Value for these options must be an IP address. Options 21, 33 must have minimum length as 8 and 8*n. Options 0, 255, 50-60 are non-configurable options. Network pool must be configured prior to the execution of this command. Only then the configured option will be visible to the user in the show command output. If the network pool.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- ip dhcp pool - Creates a DHCP server address pool and places the user in the DHCP pool configuration mode

- ip dhcp option - Sets the DHCP server options

- show ip dhcp server information - Displays the DHCP server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server statistics - Displays the DHCP server statistics

- network - Configures the network IP address of the DHCP Address Pool

### 3.4.18 `lease`

Configures the duration of the lease for an IP address that is assigned from SEFOS DHCP server to a DHCP client. The `no` form of this command restores the default value of 3600 seconds.

    lease {days_0-365 [hours_0-23 [minutes_1-59]] | infinite}

    no lease

Syntax Description | days - Duration of the lease in number of days. hours - Number of hours in lease. minutes - Number of minutes in lease. infinite - Duration of the lease is unlimited.
Mode | DHCP Pool Configuration
Defaults | 3600 seconds.
Example | SEFOS(dhcp-config)# lease 1

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the server information

- show ip dhcp server pools - Displays the DHCP server pools

- show ip dhcp server binding - Displays the DHCP server binding information

- show ip dhcp server statistics - Displays the DHCP server statistics

### 3.4.19 `utilization threshold`

Sets the pool usage threshold value in percentage. If the pool usage reaches this threshold level, a syslog event and an SNMP trap message will be generated. The `no` form of this command sets pool usage threshold to its default value.

    utilization threshold {0-100}

    no utilization threshold

Mode | DHCP Pool Configuration
Defaults | 75
Example | SEFOS(dhcp-config)# utilization threshold 76

#### Related Commands

- show ip dhcp server pools - Displays the DHCP server pools

- logging - Enables Syslog server and configures the Syslog Server IP address, the log-level and other Syslog related parameters

### 3.4.20 `host hardware-type`

Specifies the hardware address of a DHCP client and host specific DHCP options. The `no` form of the command deletes the host option.

    host hardware-type type_1-2147483647 client-identifier mac-address option code_1-2147483647 {ascii string | hex hex-string | ip address}

    no host hardware-type host-hardware-type_1-2147483647 client-identifier client-mac-address option code_1-2147483647

Syntax Description | type - Host hardware address type. client-identifier- Host MAC address. The client identifier keyword is not supported. option - The tag octet of the DHCP option. ascii - ASCII string. hex - Hex string. ip - Host IP address.
Mode | DHCP Pool Configuration
Example | SEFOS(dhcp-config)# host hardware-type 1 client-identifier 00:11:22:33:44:55 option 254 ip 10.0.0.1
Notes | The current valid values are only 0 and 1.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- ip dhcp pool - Creates a DHCP server address pool and places the user in the DHCP pool configuration mode

### 3.4.21 `debug ip dhcp server`

Enables the debug level for tracing the DHCP server module. The `no` form of this command disables the debug level for tracing the DHCP server module.

    debug ip dhcp server {all | events | packets | errors | bind | linkage}

    no debug ip dhcp server {all | events | packets | errors | bind | linkage}

Syntax Description | all - All trace messages. events - Trace management messages. packets - Packet related messages. errors - Trace error code debug messages. bind -Trace bind messages. linkage - Database linkage messages.
Mode | Privileged EXEC
Defaults | Debugging is disabled.
Example | SEFOS# debug ip dhcp server all
Notes |

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- show ip dhcp server information - Displays the server information

- show ip dhcp server binding - Displays the DHCP server binding information

### 3.4.22 `show ip dhcp server information`

Displays the DHCP server information.

    show ip dhcp server information

Mode | Privileged EXEC
Example | SEFOS# show ip dhcp server information DHCP server status : Enable Send Ping Packets : Disable Debug level : None Server Address Reuse Timeout : 5 secs Next Server Adress : 0.0.0.0 Boot file name : None

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- ip dhcp next-server - Sets the next boot server in the DHCP server configuration parameters

- ip dhcp bootfile / bootfile config-file - Sets the boot file name in the DHCP server configuration parameters

- ip dhcp - Sets the DHCP server parameters such as enabling ICMP echo mechanism or offer-reuse timeout

### 3.4.23 `show ip dhcp server pools`

Displays the DHCP server pools.

    show ip dhcp server pools

Mode | Privileged EXEC
Example | SEFOS# show ip dhcp server pools Pool Id : 1 __________________________________________ Subnet : 12.0.0.0 Subnet Mask : 255.0.0.0 Lease time : 3600 secs Utilization threshold : 75% Start Ip : 12.0.0.1 End Ip : 12.255.255.255 Subnet Options ______________ Code : 1, Value : 255.0.0.0

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- ip dhcp pool - Creates a DHCP server address pool and places the user in the DHCP pool configuration mode

- lease - Configures the duration of the lease for an IP address that is assigned from ISS Dynamic Host Configuration Protocol (DHCP) server to a DHCP client

- network - Sets the network IP and mask in DHCP server configuration parameters

- excluded-address / ip dhcp excluded-address - Creates an excluded pool to prevent DHCP server from assigning certain addresses to DHCP clients

### 3.4.24 `show ip dhcp server binding`

Displays the DHCP server binding information.

    show ip dhcp server binding

Mode | Privileged EXEC
Example | SEFOS# show ip dhcp server binding Ip Hw Hw Binding Expire Address Type Address State Time ------- ---- ------- ------ ------ 12.0.0.2 Ethernet 00:02:02:03:04:01 Assigned May 12 13:22:41 2009
Notes | Binding refers to the state of binding. This can be offered, assigned or probing. In offered state offer is sent, but no req has been received from the client. In assigned state the address is assigned to the client. In probing state the address is currently being probed by the DHCP server.

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- host hardware-type - Specifies the hardware address of a Dynamic Host Configuration Protocol (DHCP) client

- ip dhcp option - Sets the DHCP server options

### 3.4.25 `show ip dhcp server statistics`

This command displays the DHCP server statistics.

    show ip dhcp server statistics

Mode | Privileged EXEC Mode
Example | SEFOS# show ip dhcp server statistics Address pools : 2 Message Received ------- -------- DHCPDISCOVER 6 DHCPREQUEST 2 DHCPDECLINE 0 DHCPRELEASE 0 DHCPINFORM 0 Message Sent ------- ---- DHCPOFFER 6 DHCPACK 2 DHCPNAK 0

#### Related Commands

- service dhcp-server / service dhcp - Enables or disables the DHCP server

- ip dhcp pool - Creates a DHCP server address pool and places the user in the DHCP pool configuration mode

- ip dhcp - Sets the DHCP server parameters such as enabling ICMP echo mechanism or offer-reuse timeout

- show ip dhcp server pools - Displays the DHCP server pools

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