ISC DHCP server implementation has no effective methods for pool range usage monitoring.
There might be situations where the server has covered the entire possible range and ignores new devices' requests. In this case,a message (of messages) of the following type can be found in the log:
Feb 10 01:01:01 EltexDHCP dhcpd: DHCPDISCOVER from aa:bb:cc:dd:ff:00 via 100.10.1.1: peer holds all free leases
In order to count pool usage ratio and prevent such situations, dhcpd-pools utility program can be used. The utility build for ubuntu14 x64 is attached.
dhcpd-pools_2.28-1-trusty_amd64.deb
To install the program using release package, copy it to a SoftWLC server and unpack by entering:
sudo dpkg -i dhcpd-pools_2.28-1-trusty_amd64.deb
After that, run the utility with:
sudo dhcpd-pools -c /etc/dhcp/dhcpd.conf -l /var/lib/dhcp/dhcpd.leases -o ./sampleoutput.txt
where
/etc/dhcp/dhcpd.con — main DHCP server configuration file location,
/var/lib/dhcp/dhcpd.leases — lease file path,
./sampleoutput.txt — a result output file.
Project sample:
cat sampleoutput.txt Ranges: shared net name first ip last ip max cur percent touch t+c t+c perc All networks 122.0.0.10 - 122.0.0.200 191 7 3.665 47 54 28.272 All networks 123.0.0.10 - 123.0.0.200 191 2 1.047 9 11 5.759 All networks 124.0.0.10 - 124.0.0.200 191 2 1.047 57 59 30.890 All networks 200.0.0.10 - 200.0.0.30 21 0 0.000 0 0 0.000 Shared networks: name max cur percent touch t+c t+c perc Sum of all ranges: name max cur percent touch t+c t+c perc All networks 594 11 1.852 113 124 20.875
Results may include:
shared net name — the network DHCP server leases addresses from,
first ip, last ip — the first and the last addresses in the pool,
max — the pool range,
cur — the number of issued IP addresses with an active lease (addresses used to date),
percent — cur/max ratio expressed as a percentage,
touch — the number of issued IP addresses with a lease expired,
t+c — the total number of issued IP addresses;
t+c perc — t+c/max ratio, expressed as a percentage.
The utility has other opportunities as well, further information can be found on its developer's website http://dhcpd-pools.sourceforge.net/ or in the manual.