09-12-2017 03:47 AM - edited 03-05-2019 09:07 AM
Hi all.
Could you please assist me with one issue
Have dhcp conflict on 2960X
Bellow config from switch
ip dhcp excluded-address 10.151.0.1 10.151.0.20
ip dhcp excluded-address 10.151.0.100 10.151.0.150
!
ip dhcp pool DATA
network 10.151.0.0 255.255.255.0
dns-server 10.201.0.2 10.151.0.8
default-router 10.151.0.1
lease 3
spanning-tree mode pvst
spanning-tree extend system-id
!
interface Port-channel5
description server
!
interface FastEthernet0
no ip address
!
interface GigabitEthernet1/0/1
description to-ASA
switchport mode trunk
!
interface GigabitEthernet1/0/2
switchport mode access
!
interface GigabitEthernet1/0/3
switchport mode access
!
interface GigabitEthernet1/0/4
switchport mode access
!
interface GigabitEthernet1/0/5
switchport mode access
!
interface GigabitEthernet1/0/6
switchport mode access
!
interface GigabitEthernet1/0/7
switchport mode access
!
interface GigabitEthernet1/0/8
switchport mode access
!
interface GigabitEthernet1/0/9
switchport mode access
!
interface GigabitEthernet1/0/10
switchport mode access
!
interface GigabitEthernet1/0/11
switchport mode access
!
interface GigabitEthernet1/0/12
switchport mode access
!
interface GigabitEthernet1/0/13
switchport mode access
!
interface GigabitEthernet1/0/14
switchport mode access
!
interface GigabitEthernet1/0/15
switchport mode access
!
interface GigabitEthernet1/0/16
switchport mode access
!
interface GigabitEthernet1/0/17
switchport mode access
!
interface GigabitEthernet1/0/18
switchport mode access
!
interface GigabitEthernet1/0/19
switchport mode access
!
interface GigabitEthernet1/0/20
switchport mode access
!
interface GigabitEthernet1/0/21
switchport mode access
!
interface GigabitEthernet1/0/22
switchport mode access
!
interface GigabitEthernet1/0/23
switchport mode access
!
interface GigabitEthernet1/0/24
switchport mode access
!
interface GigabitEthernet1/0/25
switchport mode access
!
interface GigabitEthernet1/0/26
switchport mode access
!
interface GigabitEthernet1/0/27
switchport mode access
!
interface GigabitEthernet1/0/28
switchport mode access
!
interface GigabitEthernet1/0/29
switchport mode access
!
interface GigabitEthernet1/0/30
switchport mode access
!
interface GigabitEthernet1/0/31
switchport mode access
!
interface GigabitEthernet1/0/32
switchport mode access
!
interface GigabitEthernet1/0/33
switchport mode access
!
interface GigabitEthernet1/0/34
switchport mode access
!
interface GigabitEthernet1/0/35
switchport mode access
!
interface GigabitEthernet1/0/36
switchport mode access
!
interface GigabitEthernet1/0/37
switchport mode access
!
interface GigabitEthernet1/0/38
switchport mode access
!
interface GigabitEthernet1/0/39
switchport mode access
!
interface GigabitEthernet1/0/40
switchport mode access
!
interface GigabitEthernet1/0/41
switchport mode access
!
interface GigabitEthernet1/0/42
switchport mode access
!
interface GigabitEthernet1/0/43
switchport mode access
!
interface GigabitEthernet1/0/44
switchport mode access
!
interface GigabitEthernet1/0/45
description WiFi
switchport trunk allowed vlan 1,7
switchport mode trunk
!
interface GigabitEthernet1/0/46
description WiFi
switchport trunk allowed vlan 1,7
switchport mode trunk
!
interface GigabitEthernet1/0/47
description server
channel-group 5 mode on
!
interface GigabitEthernet1/0/48
description server
channel-group 5 mode on
!
interface GigabitEthernet1/0/49
!
interface GigabitEthernet1/0/50
!
interface TenGigabitEthernet1/0/1
!
interface TenGigabitEthernet1/0/2
!
interface Vlan1
description default
ip address 10.151.0.3 255.255.255.0
ip helper-address 10.151.0.3
1-DATA vlan (users)
7-Vlan-Guest WiFi (dhcp for guest access running on the ASA)
The problem with DHCP server for DATA (users dhcp)
Bellow log from Cisco
Sep 12 10:35:33.126: %DHCPD-4-DECLINE_CONFLICT: DHCP address conflict: client bcc3.4201.06e1 declined 10.151.0.38.
Sep 12 10:35:45.160: %DHCPD-4-DECLINE_CONFLICT: DHCP address conflict: client bcc3.4201.06e1 declined 10.151.0.40.
Sep 12 10:35:54.115: %DHCPD-4-DECLINE_CONFLICT: DHCP address conflict: client 01dc.4a3e.7f3b.00 declined 10.151.0.39.
Sep 12 10:35:57.198: %DHCPD-4-DECLINE_CONFLICT: DHCP address conflict: client bcc3.4201.06e1 declined 10.151.0.41.
Sep 12 10:36:02.927: %DHCPD-4-DECLINE_CONFLICT: DHCP address conflict: client 0154.ee75.a2da.dd declined 10.151.0.60.
Sep 12 10:36:09.229: %DHCPD-4-DECLINE_CONFLICT: DHCP address conflict: client 01dc.4a3e.7f3b.00 declined 10.151.0.42.
Sep 12 10:36:09.239: %DHCPD-4-DECLINE_CONFLICT: DHCP address conflict: client bcc3.4201.06e1 declined 10.151.0.43.
I tried to fix it with (no ip dhcp conflict logging) but it was not help
Any sollutions?
Thanks for help
09-12-2017 04:43 AM - edited 09-12-2017 04:46 AM
Hi
Try executing:
clear ip dhcp conflict address *
And see if you see the problem again. Also you could configure: ip dhcp ping <time in miliseconds>
09-12-2017 04:56 AM
09-12-2017 05:05 AM
Try
clear ip dhcp binding *
09-12-2017 05:21 AM
09-12-2017 05:30 AM - edited 09-12-2017 05:31 AM
Hi
Try removing the leasing
no lease 3 <-- 3 days.
and clear again conflict and bindings.
09-12-2017 06:20 AM
09-13-2017 12:08 PM
Hello,
it looks like the IP address of your Vlan1 interface does not match the one specified in your dhcp pool:
interface Vlan1
description default
ip address 10.151.0.3 255.255.255.0
ip helper-address 10.151.0.3
ip dhcp pool DATA
network 10.151.0.0 255.255.255.0
dns-server 10.201.0.2 10.151.0.8
default-router 10.151.0.1
lease 3
Change the default router to the Vlan 1 IP address:
interface Vlan1
description default
ip address 10.151.0.1 255.255.255.0
ip helper-address 10.151.0.3
ip dhcp pool DATA
network 10.151.0.0 255.255.255.0
dns-server 10.201.0.2 10.151.0.8
default-router 10.151.0.1
lease 3
Also, what is the purpose of the IP helper address, is there a(nother) DHCP server configured at that address ? Try and remove that altogether:
interface Vlan1
description default
ip address 10.151.0.1 255.255.255.0
--> no ip helper-address 10.151.0.3
09-14-2017 04:10 AM
Hello
You need to apply a dhcp relay to the switch if the switch itself is providing the allocation.
You need to remove it
res
Paul
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