Find Free IP addresses from DHCP configuration file.

ips-available.py

#!/usr/bin/python
import re
config_file='/etc/dhcpd.conf'
ips_used=[]
not_used=[]
try :
    dhcp_config=open(config_file,'r')

    for lin in dhcp_config :
        match=re.search(r'^fixed-address\ \d+\.\d+\.\d+\.(\d+);',lin) 
        if match :
             ips_used.append(match.group(1))
#print ips_used

    for i in range(1,254) :
         if str(i) not in ips_used :
               not_used.append(i)
    print "IP addresses available in 192.168.1.0/24"
    print not_used
except: 
     print "Not able to find DHCP config file."
finally:
    dhcp_config.close()