DHCP

[ravi mishra]

in my office, people bring their laptops and connect to the network.Since we have dhcp allocation of ip addresses,an ip is provided to them and once they disconnect, the address is still in an allocated state in the dhcp server. Can anyone tell me how we can effectively release such allocated but unused ip addresses.Any dhcp based command to do it ????

[nkarthikeyan]

Hi Ravi,

Because you have the dhcp lease period configured for each ip address that releases..... until and unless ip address lease period expires it will not release the allocated ip address to any other machines..... you can minimize the lease period as per your requirement and you can try...

Regards

Karthik

[ravi mishra]

i did the same ,put in dhcp lease ,to test it ,i kept the time to 1 hour but it didnt change..the dhcp ips remained same

[nkarthikeyan]

Hi Ravi,

until and unless a exhausion of the free ip address, it will not release the new ip address.....

say for example you have /29 - DHCP, which can release 5 IP adresses for 5 hosts..... you have connected only 3 hosts now.... you have set your dhcp lease 1 hr.... if you remove host 3 from network for more than 1 hr and of you connect back it will give you the same ip address only.....

example:

It released only 10.0.0.0/29 - 10.0.0.2, 10.0.0.3, 10.0.0.4....

free ip's : 10.0.0.5 and 10.0.0.6....

It will release the new ip when host 3 is removed from network for more than one hour... say 2 hrs.... another 3 hosts connected to the network during this period.... say its connected after one hr after the removal of host 3 (10.0.0.3).... new hosts will get 10.0.0.5, 10.0.0.6, 10.0.0.3 (after the lease period)- This ip is allocated to new host...

Regards

Karthik