DHCP Conflict on switch core

[Nadia km]

Hey.

I am facing issue with releasing one reserved IP from dhcp pool.

I got "Address  172.***.***.*** is not reserved. Use the clear binding command" message when i wrote " no address 172.***.***.*** client-id ****.****.****.** " , however, if I write "clear ip dhcp bind  172.***.***.*** " it is showed "Address 172.***.***.*** is not in the database " to me.

sw version = 16.12.05b

model = WS-C3850-24T

[balaji.bandi]

Can you post the DHCP Config (Hope switch doing DHCP reservation here)

show dhcp IP binding - post here

[Nadia km]

 

[balaji.bandi]

Post output rather screenshots here  - so easy to read :

here is bold in my suggestions :

ip dhcp excluded-address 172.x.x.x (this is gateway IP and range for reserver IP Address to be here)

ip dhcp pool myPool
network 172.x.x.x 255.255.255.128
default-router 172.x.x.x
dns-server 192.168.x.x 192.168.x.x
lease 7 23 59
address 172.x.x.x client-id x.x.x.x  ( MAC address need to be add As it is connected using Ethernet media then you have to add 01 before the MAC Address as

[Nadia km]

I don't exclude any range of IP.

I had to reboot my switch and my problem is solved :))

[balaji.bandi]

that is a short-term fix,. but the Long term suggests to exclude, so it is not part of DHCP scope to allocate an IP address that is statically configured, which DHCP Sever is not aware of.

[MHM Cisco World]

You are correct 

[Georg Pauwen]

Hello,

try and disable/enable the DHCP service, that sometimes helps"

3850#conf t

3850(config)#no service dhcp

3850(config)#service dhcp

[Nadia km]

what happens if I disable DHCP server? Dose it make trouble for another configuration or users who got ip ?

[jamesduv9]

Posting the output of show run | sec dhcp would be helpful.

Is it possible that the 172.x.x.x subnet and the DHCP pool are associated with a VRF?

[Nadia km]

ip dhcp pool myPool
network 172.x.x.x 255.255.255.128
default-router 172.x.x.x
dns-server 192.168.x.x 192.168.x.x
lease 7 23 59
address 172.x.x.x client-id x.x.x.x

[MHM Cisco World]

Your config is OK except 
you must config the exclude for ip address for host with client-id 
if you not config the exclude the DHCP try to assign IP to other host.

[Nadia km]

Hey

I am facing this problem again.

I can't release an IP that i reserved for host. (DHCP doesn't assign the IP for host)

Could you help me?

[MHM Cisco World]

Dont worry, 
show the last dhcp config, 
show ip dhcp binding 
show ip dhcp conflict 
show ip dhcp database