Cisco phone renew DHCP IP

[vin.marco]

Hi everyone I have a problem with the DHCP server. I created a DHCP server in the Catalyst 9400 for a VoIP Vlan.

Everything works, but when I restart the phone, it takes a new address.
Why ?

I attach the DHCP configuration:

!
ip dhcp excluded-address vrf XXXXXXX 10.77.2.1 10.77.2.10
!
ip dhcp pool VoIP_UC14_V1200
 vrf XXXXXXX
 network 10.77.2.0 255.255.254.0
 default-router 10.77.2.1 
 option 150 ip 10.77.8.132 10.77.0.132 
 dns-server 10.30.47.151 10.30.47.158 
!

[MHM Cisco World]

You do restart so sure phone not keep IP it get before restart and hence ask new IP.

If ypu face issue in dhcp exhaust then try reduce dhcp lease time to be 30 min

MHM

[Maren Mahoney]

The phone should get the same address until (at least) the lease expires. If you need a phone to have a manually assigned IP you can create a DHCP Pool for that one address with the static IP and the client-id of the endpoint. 

ip dhcp pool <POOLNAME>
  host static.ip.add.here 255.255.255.255
  client-identifier <client-id>

I suspect you have this link or a similar link already, but here is DHCP information for IOS-XE 17 (which doesn't change much):

https://www.cisco.com/c/en/us/td/docs/routers/ios/config/17-x/ip-addressing/b-ip-addressing/m_config-dhcp-server-xe.html

Maren

[Nithin Eluvathingal]

The default lease time for DHCP is one day on a Cisco device, unless it’s been modified. On a Windows server, the default lease is eight days. Phones that have acquired new IP addresses may have had their leases expired.

You can set a longer lease duration under the DHCP pool using the ‘lease days [hours] [minutes]’ command. Another option is to statically assign the IP address with the MAC, as @Maren Mahoney suggested. This ensures that the phone always receives the same IP.

[vin.marco]

thanks everyone for the support,

I'll try to increase the lease

[Joel Benicio Contreras Cid]

Hi. Can you indicate if the phone is registered in Webex Calling or CUCM? It happened to me that with the MPP firmware I had that condition.

[vin.marco]

the phones are registered in CUCM, not managed by me.
The Catalyst 9400 act as DHCP Server