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Monitoring DHCP Services

 

Purpose

Note

This topic applies only to the J-Web Application package.

A switch or router can operate as a DHCP server. Use the monitoring functionality to view information about dynamic and static DHCP leases, conflicts, pools, and statistics.

Action

To monitor the DHCP server in the J-Web interface, select Monitor > Services > DHCP.

To monitor the DHCP server in the CLI, enter the following CLI commands:

  • show system services dhcp binding

  • show system services dhcp conflict

  • show system services dhcp pool

  • show system services dhcp statistics

  • show system services dhcp relay-statistics

  • show system services dhcp global

  • show system services dhcp client

  • clear system services dhcp binding

  • clear system services dhcp conflict

  • clear system services dhcp statistics

  • clear dhcp relay-statistics

On EX4300 switches, to monitor the DHCP server in the CLI, enter the following CLI commands:

  • show dhcp server binding

  • show dhcp server statistics

  • show dhcp relay binding

  • show dhcp relay statistics

  • clear dhcp server binding

  • clear dhcp server statistics

  • clear dhcp relay binding

  • clear dhcp relay statistics

Meaning

Table 91 summarizes the output fields in DHCP displays in the J-Web interface.

Table 91: Summary of DHCP Output Fields

Field

Values

Additional Information

Global tab

Name

This column displays the following information:

  • Boot lease length

  • Domain Name

  • Name servers

  • Server identifier

  • Domain search

  • Gateway routers

  • WINS server

  • Boot file

  • Boot server

  • Default lease time

  • Minimum lease time

  • Maximum lease time

 

Value

Displays the value for each of the parameters in the Name column.

 
Bindings tab

Allocated Address

List of IP addresses the DHCP server has assigned to clients.

 

MAC Address

Corresponding media access control (MAC) address of the client.

 

Binding Type

Type of binding assigned to the client: dynamic or static.

DHCP servers can assign a dynamic binding from a pool of IP addresses or a static binding to one or more specific IP addresses.

Lease Expires

Date and time the lease expires, or never for leases that do not expire.

 
Pools tab

Pool Name

Subnet on which the IP address pool is defined.

 

Low Address

Lowest address in the IP address pool.

 

High Address

Highest address in the IP address pool.

 

Excluded Addresses

Addresses excluded from the address pool.

 
Clients tab

Interface Name

Name of the logical interface.

 

Hardware Address

Vendor identification.

 

Status

State of the client binding.

 

Address Obtained

IP address obtained from the DHCP server.

 

Update Server

Indicates whether server update is enabled.

 

Lease Obtained

Date and time the lease was obtained.

 

Lease Expires

Date and time the lease expires.

 

Renew

Reacquires an IP address from the server for the interface. When you click this option, the command sends a discover message if the client state is INIT and a renew request message if the client state is BOUND. For all other states it performs no action.

 

Release

Clears other resources received earlier from the server, and reinitializes the client state to INIT for the particular interface.

 
Conflicts tab

Detection Time

Date and time the client detected the conflict.

 

Detection Method

How the conflict was detected.

Only client-detected conflicts are displayed.

Address

IP address where the conflict occurs.

The addresses in the conflicts list remain excluded until you use the clear system services dhcp conflict command to manually clear the list.

DHCP Statistics
Relay Statistics tab

Packet Counters

Displays the number of packet counters.

 

Dropped Packet Counters

Graphically displays the number of dropped packet counters.

 
Statistics tab

Packets dropped

Total number of packets dropped and the number of packets dropped due to a particular condition.

 

Messages received

Number of BOOTREQUEST, DHCPDECLINE, DHCPDISCOVER, DHCPINFORM, DHCPRELEASE, and DHCPREQUEST messages sent from DHCP clients and received by the DHCP server.

 

Messages sent

Number of BOOTREPLY, DHCPACK, DHCPOFFER, DHCPNAK, and DHCPFORCERENEW messages sent from the DHCP server to DHCP clients.

 

Table 92 summarizes the output fields in DHCP displays in EX4300 switches in the J-Web interface.

Table 92: Summary of DHCP Output Fields for EX4300 Switches

Field

Values

Additional Information

Binding Information tab

IP Address

IP address of the DHCP client..

 

Session ID

Session ID of the subscriber session.

 

Hardware Address

Hardware address of the DHCP client.

 

Expires

Number of seconds in which the lease expires.

 

State

State of the address binding table on the extended DHCP local server:

  • BOUND—Client has an active IP address lease.

  • FORCERENEW—Client has received the FORCERENEW message from the server.

  • INIT—Initial state.

  • RELEASE—Client is releasing the IP address lease.

  • RENEWING—Client is sending a request to renew the IP address lease.

  • REQUESTING—Client is requesting a DHCP server.

  • SELECTING—Client is receiving offers from DHCP servers.

 

Interface

Interface on which the request was received.

 

Table 93 summarizes the output fields in DHCP Statistics Information for EX4300 switches in the J-Web interface.

Table 93: Summary of the DHCP Statistics Information Output for EX4300 switches

Field

Values

Additional Information

Message Counters

Message Counters

Graphically displays the number of messages sent and received.

 

Dropped packet Counters

MAC Limit

Graphically displays the number of dropped packet counters.