NAME¶

dhcpd-pools - ISC dhcpd pools usage analysis

SYNOPSIS¶

DESCRIPTION¶

The program analyses ISC dhcpd shared network and pool usage and outputs the results in a format selected by user.

OUTPUT FIELDS¶

shared net name

Name of the shared-network for the range.

first ip

First IP in lease pool range.

last ip

Last IP in lease pool range.

max

Number of IPs which exist in a pool, shared network or all together.

cur

Number of leases currently in use.

percent

Percent of IPs currently in use compared to max.

touch

Number of IP's which appear in the lease file, but who's leases have expired. A touched IP is either expired or abandoned. The touched IP count is somewhat misleading when you try to determine if an IP pool is big enough; it is a better indicator of whether a pool is too large.

t+c

The sum of Touched and Currently in-use leases.

t+c perc

Percent of IPs either touched or currently in use, compared to max.

bu

Failover pair can allocate these addresses. The count appears only if there is failover configuration.

bu perc

Percent of addresses that failover pair can allocate. The percent appears only if there is failover configuration.

OPTIONS¶

-c, --config=FILE

Path to the dhcpd.conf file. If the dhcpd.conf has include files they can be analysed separately, that can be useful when trying to understand or monitor subset of data.

-l, --leases=FILE

Path to the dhcpd.leases file.

-s, --sort=[nimcptTe]

Sort ranges by chosen fields as a sorting keys. Keys weight from left to right, i.e., if more weighting keys are equal next one is used. The IP field is default sort key.

-r, --reverse

Sort results in reverse order.

-f, --format=[tHcxXjJ]

Output format. Text (t). Full-html (H) page output. The (c) stands for comma-separated values. Output format xml (x) is similar to the dhcpstatus Perl module output. The extended xml (X) format will print ethernet address details. The (j) will output in json format, which can be extended with (J) to include ethernet address.

The default format is text.

-o, --output=FILE

File where output is written. Default is stdout.

-L, --limit=NR

The NR will limit what will be printed. Syntax is similar to chmod(1) permission string. The NR limit string uses two digits which vary between 0 to 7. The first digit determines which headers to display, and the second digit determines which numeric analysis tables to include in the output. The following values are "OR'd" together to create the desired output. The default is 77.

01	Print ranges
02	Print shared networks
04	Print total summary
10	Print range header
20	Print shared network header
40	Print total summary header

The output limit for total summary has special meaning in --warning and --critical alarming context. When the alarming is in use, and total is not wanted to be seen then in the case of alarming returning success nothing is printed.

--warning=percent

Turn on alarm output format, and specify percentage number which will cause an alarm. If either a range or shared network will exceed warning level return value of the command is 1. If only range monitoring is needed one can use limit option for scoping, for example -L10. To monitor shared network only the limit would be -L20. If warning percentage is not specified it defaults to 80. The percent argument allows fractions, e.g., 88.8, to be used.

--critical=percent

The option is similar to warning, with exception of return value which is 2. If critical percentage is not specified it defaults to 90.

--warn-count=number

A number of free leases before alarm is raised. When specified both --warning percent and count number are required to be exceeded in order to alarm criteria being fulfilled.

This option is intended to be used in setup where very large and small shared-networks and ranges co-exists. In such environments percent based alarming can lead to either flood of alarms about small ranges, or way too great overhead of free addresses in large shared-networks. Suggested usage is to set percentage to a level that makes small ranges to ring, and set the count to match level when an enormous shared-network is too few free leases.

Defaults to 2^32, that is size of entire IPv4 address space.

--crit-count=number

Same as --warn-count, but for critical alarms.

--snet-alarms

Suppress range alarms that are part of shared networks. Use of this option will keep alarm criteria applied to ranges that are not part of shared-net along with shared-net alarms. This option may help reducing alarm noise for configurations that has lots of small ranges in big shared-networks.

--minsize=size

Ignore ranges and shared networks that are smaller or equal to the defined size. This option is meaningful only in context of alarming, and will intended to suppress for example single host ranges. By default this option is not in use.

-p, --perfdata

Print additional performance data, like lease count, touched leases and backup leases. This option is meaningful only in context of alarming and will print lots of data, if there are many networks. By default this option is not in use.

-A, --all-as-shared

Treat all stand-alone subnets as shared-network with named formed from it's CIDR. By default this option is not in use for backwards compatibility.

--ip-version=4|6

Force command to read configuration and leases files in IPv4 or IPv6 mode. Notice that when inputs do not match with what is forced analysis output is garbage. This option should not be necessary to use, and exists only to allow debugging.

-v, --version

Print version information to standard output and exit successfully.

-h, --help

Print help to standard output and exit successfully.

EXAMPLES¶

Print ranges header, and analysis.

$ dhcpd-pools -L 11 -c dhcpd.conf -l dhcpd.leases
Ranges:
shared net name [...]

Print shared networks and totals, both headers and results

$ dhcpd-pools -L 66 -c dhcpd.conf -l dhcpd.leases shared net name
[...]

Alarming

$ dhcpd-pools -c dhcpd.conf -l dhcpd.leases --critical 80.1 --warning 75
CRITICAL: dhcpd-pools: Ranges; crit: 14 warn: 22 ok: 220 Shared nets; crit: 1 warn: 0 ok: 4

$ dhcpd-pools -c dhcpd.conf -l dhcpd.leases -L 22 --critical 70 --warning 50
[no-output]
Suppress printing OK, and make alarm only to go off if shared networks exceed critial or warning levels.

FILES¶

/etc/dhcp/dhcpd.conf

ISC dhcpd configuration file.

/var/lib/dhcp/dhcpd.leases

ISC dhcpd lease file.

AUTHORS¶

Original design by Sami Kerola.
XML support by Dominic Germain, Sogetel inc.
IPv6 support by Cheer Xiao.

The software has FreeBSD License.

REPORTING BUGS¶

Report bugs to Sami Kerola
Home page

SEE ALSO¶

dhcpd.leases(5), dhcpd.conf(5), chmod(1)