C9300 Coreswitch DHCP issue

[rcreddy-e]

May 21 11:05:43.163: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 11:53:29.229: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 12:17:21.289: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 12:29:15.634: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 12:35:14.700: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 12:38:13.747: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 12:39:43.792: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 12:40:53.876: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 13:48:21.520: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 14:10:47.028: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 14:56:01.120: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
--More--  May 21 15:04:30.914: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 15:07:29.705: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 15:24:22.868: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 15:32:49.888: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 15:37:01.951: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 15:39:09.024: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 15:40:11.049: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e41f.d505.50fa reason CANT FORWARD
May 21 15:40:55.952: %DHCPD-7-NAK: DHCP nak sent to client 01e4.1fd5.0550.fa
May 22 15:15:36.761: %DHCPD-4-PING_CONFLICT: DHCP address conflict: server pinged 192.168.10.85.
May 22 15:15:36.764: %DHCPD-4-PING_CONFLICT: DHCP address conflict: server pinged 192.168.10.87.
May 22 15:15:36.765: %DHCPD-4-PING_CONFLICT: DHCP address conflict: server pinged 192.168.10.88.
May 23 13:23:12.916: %SW_MATM-4-MACFLAP_NOTIF: Host c447.4e2d.043d in vlan 110 is flapping between port Te1/1/1 and port Gi1/0/17
--More--  May 25 05:30:51.562: %DHCPD-7-RELEASE: DHCP release request, client 0130.e3a4.9de8.dd
May 27 06:52:51.370: %DHCPD-7-NAK: DHCP nak sent to client 0128.7fcf.b107.42
May 29 08:57:36.270: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client e86a.648f.7f46 reason CLIENT CHANGED SUBNET
May 29 08:57:36.271: %DHCPD-7-NAK: DHCP nak sent to client 01e8.6a64.8f7f.46
May 29 09:29:09.546: %DHCPD-7-NO_LEASE: DHCP lease assignment failure, client 4c03.4ffc.1494 reason CLIENT CHANGED SUBNET
May 29 09:29:09.546: %DHCPD-7-NAK: DHCP nak sent to client 014c.034f.fc14.94
May 29 13:22:54.701: %DHCPD-7-NAK: DHCP nak sent to client 01e4.1fd5.0550.fa
May 29 13:34:21.728: %DHCPD-7-NAK: DHCP nak sent to client 0128.7fcf.b107.42

[Mark Elsen]

  - @rcreddy-e                  Make sure to configure an ip helper address if the DHCP server is not on the
                                         VLAN those clients are operating in : an example below.
                                                      interface Vlan10
                                                      ip address 192.168.10.1 255.255.255.0
                                                      ip helper-address 10.1.1.100
                                                      no shutdown

 M.

[rcreddy-e]

No ip helper-address 10.1.1.100 

ip dhcp pool vlan10
network 192.168.10.0 255.255.255.0
default-router 192.168.10.1
dns-server  8.8.8.8 8.8.4.4
lease 0 8

We have configured the DHCP pool for VLAN10 with the below settings:

• Network: 192.168.10.0/24
• Default Gateway: 192.168.10.1
• DNS Servers: 8.8.8.8, 8.8.4.4
• Lease Time: 8 Hours

Also, the ip helper-address 10.1.1.100 configuration is currently not enabled.

At present, devices with static IP addresses are working fine. However, DHCP IP addresses are not being assigned/released to client devices.

Could you please check and confirm if there are any missing configurations or issues from the DHCP server side?

Please let us know your observations.

[Mark Elsen]

  - @rcreddy-e                      >....., the ip helper-address 10.1.1.100 configuration is currently not enabled.
                               If the DHCP server is not in Vlan10 then using the ip-helper address directive becomes
                               mandatory.

  M.

[Giuseppe Larosa]

Hello @rcreddy-e ,

it looks like your switch is configured as DHCP server for VLAN10.

>> ip dhcp pool vlan10
network 192.168.10.0 255.255.255.0
default-router 192.168.10.1
dns-server 8.8.8.8 8.8.4.4
lease 0 8

Configuration is fine if the switch has SVI interface vlan10 configured and up/up.

as suggested post also the configuration of interface vlan10 an outgoing IP ACL applied to it may be present.

>> 

check how many IP addresses are assigned from the pool 

show ip dhcp binding

Edit:

view

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/xe-16-12/dhcp-xe-16-12-book/config-dhcp-server-xe.html#GUID-762B82CC-87B7-44BA-9813-45BE50962D29

Hope to help

Giuseppe

[Singhaam]

i guess you check the ip helper address and make sure not routing issues or firewall blocking UDP 67/68 traffic 

[Singhaam]

whats your sh run int VLAN10 config ?