kam_uk
asked on
DHCP query relating to leases
Hi
I have a query with DHCP that I was hoping someone could help me with.
Let's say I have a subnet of 192.168.10.1/24.
DHCP is configured to lease addresses from 192.168.10.10 - 192.168.10.20. The rest are static. The lease time is 7 days.
On Monday, I build 11 new machines that use up all the DHCP addresses.
I then take them offline and store them somewhere.
On Tuesday, if I place a new DHCP client enabled machine on the network, will it pick up an IP address from DHCP, or do I have to wait 6 days? Bearing in mind that the original 11 machines are offline, but still within their lease time.
Cheers
I have a query with DHCP that I was hoping someone could help me with.
Let's say I have a subnet of 192.168.10.1/24.
DHCP is configured to lease addresses from 192.168.10.10 - 192.168.10.20. The rest are static. The lease time is 7 days.
On Monday, I build 11 new machines that use up all the DHCP addresses.
I then take them offline and store them somewhere.
On Tuesday, if I place a new DHCP client enabled machine on the network, will it pick up an IP address from DHCP, or do I have to wait 6 days? Bearing in mind that the original 11 machines are offline, but still within their lease time.
Cheers
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
Hi
Thanks...so, just to confirm, the DHCP server doesn't check to see if the original 11 machines are still connected? It will reserve their IP addresses regardless?
Thanks...so, just to confirm, the DHCP server doesn't check to see if the original 11 machines are still connected? It will reserve their IP addresses regardless?
ASKER
..and if we do intend to take the machines off the network, we should do an ip/release?
kam_uk,
That is correct. The DHCP Server has no idea that the machines have left the network, because a machine will not automatically release an IP address before it is switched off.
You can either ipconfig /release the machine before you take it off the network, or delete the IP lease from the Address Leases section on the DHCP Server. Only when an IP is not listed in Address Leases can it then be placed back into the pool of addresses for leasing again.
Of course, the other option is just to ensure your IP pool is large enough to have plenty of surplus addresses.
-tigermatt
That is correct. The DHCP Server has no idea that the machines have left the network, because a machine will not automatically release an IP address before it is switched off.
You can either ipconfig /release the machine before you take it off the network, or delete the IP lease from the Address Leases section on the DHCP Server. Only when an IP is not listed in Address Leases can it then be placed back into the pool of addresses for leasing again.
Of course, the other option is just to ensure your IP pool is large enough to have plenty of surplus addresses.
-tigermatt
No DHCP does not - and cannot check that the machines are still connected, until the lease runs out, their IP addresses cannot be assigned to another machine.
Yes you could to an ipconfig /release, bit if you have a big enough pool of addresses, it does not matter
The other alternative is to reduce the lease period so that the leases become available more quickly.
Yes you could to an ipconfig /release, bit if you have a big enough pool of addresses, it does not matter
The other alternative is to reduce the lease period so that the leases become available more quickly.
http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/cnet/cncb_dhc_fioy.mspx?mfr=true
Thanks