How to find free ip addresses in dhcpd.conf?

Question

linux

There is a rather long dhcpd.conf file with ip addresses from different subnets. Can you tell me how to find free addresses? Using grep, I tore out all the lines from the file with addresses from the subnet I needed, I want to find out the unoccupied addresses.

Answer 1

Understood, in general, I publish the solution:

for ip in 192.168.0.{254..1} ; do
    grep -oE "$ip" dhcpd.conf > /dev/null 2>&1
    if [ $? != 0 ] ; then
        echo "$ip is free"
    fi
done

Answer 2

Look for the line in the config:
range 192.168.0.20 192.168.0.260
This will be all the IP addresses reserved by the dhcp server, subtracting the free ones is not at all difficult.