Monitoring DHCP Services
Purpose
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
Meaning
Table 1 summarizes the output fields in DHCP displays in the J-Web interface.
Field |
Values |
Additional Information |
---|---|---|
Global tab | ||
Name |
This column displays the following information:
|
|
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 |
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. |