Monitoring DHCP Services
Purpose
A switch can operate as a DHCP server. When it is 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
Meaning
Table 1 summarizes
the output fields in DHCP displays.
Table 1: Summary of DHCP Output Fields
|
Field
|
Values
|
Additional Information
|
| DHCP Leases
|
|
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.
| |
| DHCP Conflicts
|
|
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 Pools
|
|
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.
| |
| DHCP Statistics
|
|
Default lease time
|
Lease time assigned to clients that do not
request a specific lease time.
| |
|
Minimum lease time
|
Minimum time a client can retain an IP address
lease on the server.
| |
|
Maximum lease time
|
Maximum time a client can retain an IP address
lease on the server.
| |
|
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, and
DHCPNAK messages sent from the DHCP server to DHCP clients.
| |
