Cisco 3850 IP dhcp pool IP address released

[anirbanshil.ars1]

I want to know maximum how many ip address can be released from ip dhcp pool on cisco 3850 switch.

Regards 

Anirban Shil

[anirbanshil.ars1]

Please anyone help me!!!!

[Seb Rupik]

Hi there,

Is your question 'how many DHCP scopes can be configured', or 'how do you release DHCP bindings'?

cheers,

Seb.

[anirbanshil.ars1]

Actually my question is "how do I release DHCP bindings in a ip dhcp pool".

Also How can remove/release dhcp ip from a specific pool.

[Seb Rupik]

With the following command:

clear ip dhcp binding <ip_address>

[anirbanshil.ars1]

Hi Seb,

How can release dhcp ip from a specific pool?

[Seb Rupik]

Hi there,

If you wan to release a DHCP lease, firstly confirm the lease is active:

sh ip dhcp binding

...then once you have confirmed the lease, use the command mentioned earlier, eg:

clear ip dhcp binding 192.168.100.69

You do not need to mention the pool where the lease was obtained from.

cheers,

Seb.

[anirbanshil.ars1]

Hi Seb,

I applied dhcp in the pool not interface so that i want to release all dhcp ip from this pool. I have no ip binding. I can see all ip address from show arp. I have configured multiple dhcp pool.

Actually I want to release all ip address from a specific pool.

Is it possible?

Regards 

Anirban Shil

[joshinirmit01]

Hi Anir,

yes you can release all IP from specific pool.

But for batter explanation can you show basic diagram or explain DHCP Pool and network details?

Regards,

Nirmit

[anirbanshil.ars1]

Hi there,

How can I release all IP from specific pool MLAN? 

Not another pool just release from dhcp pool MLAN.

Please find the attached screenshot. 

Code:

--------------------------------------

interface VLAN 10

ip address 192.168.10.1 255.255.255.0

!

interface VLAN 20

ip address 192.168.20.1 255.255.255.0

!

interface VLAN 100

ip address 192.168.100.1 255.255.255.0

!

IP excluded 192.168.10.1-192.168.10.15

IP excluded 192.168.20.1-192.168.20.15

IP excluded 192.168.100.1-192.168.100.15

!

ip dhcp pool LAN

network 192.168.10.0/24

domain-name cisco.com

dns server 192.168.10.1 8.8.8.8

default-router 192.168.10.1

!

ip dhcp pool WLAN

network 192.168.20.0/24

domain-name cisco.com

dns server 192.168.20.1 8.8.8.8

default-router 192.168.20.1

!

ip dhcp pool MLAN

network 192.168.100.0/24

domain-name cisco.com

dns server 192.168.100.1 8.8.8.8

default-router 192.168.100.1

!

[Seb Rupik]

Hi there,

From your description it sounds like you have created a DHCP scope on a subnet which already has active IP addresses, either issued from another DHCP server or statically assigned. Either way you will not be able to release or force the end devices to renew their IP addresses from the router in question.

You first need to determine that your router is the only DHCP server for the subnet, then you will need to visit the devices in the ARP table and ensure their interfaces are configured for DHCP. Bounce their interfaces and you should see them in the DHCP bindings on your router.

cheers,

Seb.

[anirbanshil.ars1]

Hi Seb,

Thank you. 

[balaji.bandi]

Apart from Gateway Router IP, you can release all the IP

example : for /24 subnet

192.168.1.0/24

Gateway IP excluded 192.168.1.1 (thinking that 1 is gateway)

you can use 192.168.1.2-192.168.1.254

is this make sense ?

[anirbanshil.ars1]

HI Balaji,

yes, But we have configured ip dhcp pool.

Here,

----------------------------

interface VLAN 100

ip address 192.168.100.1 255.255.255.0

!

IP excluded 192.168.100.1-192.168.100.15

!

ip dhcp pool name1

network 192.168.100.0/24

domain-name cisco.com

dns server 192.168.10.1 8.8.8.8

default-router 192.168.100.1

!

---------------------------

Question: How can release dhcp ip from a specific pool name1?