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New Member

%DTL-3-ARP_CLIENT_IP_DUPLICATED

Dear All,

I am getting this error in my WLC. More that 50 users are unable to pick up ip address from DHCP server and the connected users are getting RTO in our network also. Please somebody help me why is happening like this and what is the meaning of the error???????????

*DHCP Socket Task: Jul 18 13:30:49.650: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1802 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  ffffffc0:18:ffffff85:74:ffffffc5:28 and IP Address  172.28.1.128, Old client MAC-ID was

*DHCP Socket Task: Jul 18 13:30:45.478: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1802 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  ffffffc0:18:ffffff85:74:ffffffd4:ffffff86 and IP Address  172.28.1.114, Old client MAC-

*DHCP Socket Task: Jul 18 13:30:30.384: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1802 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  20:7c:ffffff8f:32:ffffffdf:ffffff96 and IP Address  172.28.1.34, Old client MAC-ID was

Regards,

Sanjib Pradhan

  • Getting Started with Wireless
8 REPLIES
New Member

Hi,

Hi,

How did you solved this issue ?

Hall of Fame Super Silver

Catalin,

Catalin,

Can you provide more information in regards to what you are seeing.  Duplicate address can be an issue with wireless especially is DHCP scopes overlap. 

-Scott

Thanks, Scott *****Help out other by using the rating system and marking answered questions as "Answered"*****
New Member

Hi,

Hi,

This is what is see in the logs:

*DHCP Socket Task: Dec 01 12:16:08.787: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1813 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  2c:33:7a:7f:b5:d1 and IP Address  10.10.9.3, Old client MAC-ID was a0:39:f7:54:d7:70
*DHCP Socket Task: Dec 01 12:14:03.849: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1813 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  40:f3:08:54:92:a1 and IP Address  10.10.9.1, Old client MAC-ID was a0:39:f7:54:d7:70
*DHCP Socket Task: Dec 01 12:09:43.395: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1813 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  10:d3:8a:60:d8:cc and IP Address  10.10.8.251, Old client MAC-ID was a0:39:f7:54:d7:70
*DHCP Socket Task: Dec 01 12:07:14.475: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1813 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  90:48:9a:19:7c:65 and IP Address  10.10.8.245, Old client MAC-ID was a0:39:f7:54:d7:70
*DHCP Socket Task: Dec 01 11:59:31.704: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1813 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  b8:ee:65:0d:94:35 and IP Address  10.10.8.240, Old client MAC-ID was a0:39:f7:54:d7:70
*DHCP Socket Task: Nov 30 15:39:00.147: %DTL-3-ARP_CLIENT_IP_DUPLICATED: dtl_arp.c:1813 ARP entry overwrite, conflict detected via ARP Request from client with MAC-ID  74:de:2b:29:47:e5 and IP Address  10.10.8.140, Old client MAC-ID was a0:39:f7:54:d7:70

Clients complaining that they are disconnecting periodically.

The DHCP server in running on Juniper SRX 240H2 - 12.1X46-D40.2

I have on the network Cisco WLC - 2504 - running - 8.1.122.0

Thank you,

Hall of Fame Super Silver

Well what are they really

Well what are they really complaining of and what is the design?  Post your show WLAN <WLAN Id> and explain in more detail what is happening. 

-Scott

Thanks, Scott *****Help out other by using the rating system and marking answered questions as "Answered"*****
New Member

Hi,

Hi,

Please see output below:

(Cisco Controller) >show wlan 1


WLAN Identifier.................................. 1
Profile Name..................................... XXXX
Network Name (SSID).............................. XXXX
Status........................................... Enabled
MAC Filtering.................................... Disabled
Broadcast SSID................................... Enabled
AAA Policy Override.............................. Disabled
Network Admission Control
Client Profiling Status
    Radius Profiling ............................ Disabled
     DHCP ....................................... Disabled
     HTTP ....................................... Disabled
    Local Profiling ............................. Disabled
     DHCP ....................................... Disabled
     HTTP ....................................... Disabled
  Radius-NAC State............................... Disabled
  SNMP-NAC State................................. Disabled
  Quarantine VLAN................................ 0
Maximum number of Associated Clients............. 0
Maximum number of Clients per AP Radio........... 200

--More-- or (q)uit
ATF Policy....................................... 0
Number of Active Clients......................... 236
Exclusionlist Timeout............................ 60 seconds
Session Timeout.................................. 28800 seconds
User Idle Timeout................................ Disabled
Sleep Client..................................... disable
Sleep Client Timeout............................. 720 minutes
User Idle Threshold.............................. 0 Bytes
NAS-identifier................................... M6-PARTER-1
CHD per WLAN..................................... Enabled
Webauth DHCP exclusion........................... Disabled
Interface........................................ management
Multicast Interface.............................. Not Configured
WLAN IPv4 ACL.................................... unconfigured
WLAN IPv6 ACL.................................... unconfigured
WLAN Layer2 ACL.................................. unconfigured
mDNS Status...................................... Disabled
mDNS Profile Name................................ unconfigured
DHCP Server...................................... Default
DHCP Address Assignment Required................. Enabled
Static IP client tunneling....................... Disabled
Tunnel Profile................................... Unconfigured
Quality of Service............................... Silver

--More-- or (q)uit
Per-SSID Rate Limits............................. Upstream      Downstream
Average Data Rate................................   0             0
Average Realtime Data Rate.......................   0             0
Burst Data Rate..................................   0             0
Burst Realtime Data Rate.........................   0             0
Per-Client Rate Limits........................... Upstream      Downstream
Average Data Rate................................   0             0
Average Realtime Data Rate.......................   0             0
Burst Data Rate..................................   0             0
Burst Realtime Data Rate.........................   0             0
Scan Defer Priority.............................. 4,5,6
Scan Defer Time.................................. 100 milliseconds
WMM.............................................. Allowed
WMM UAPSD Compliant Client Support............... Disabled
Media Stream Multicast-direct.................... Disabled
CCX - AironetIe Support.......................... Enabled
CCX - Gratuitous ProbeResponse (GPR)............. Disabled
CCX - Diagnostics Channel Capability............. Disabled
Dot11-Phone Mode (7920).......................... Disabled
Wired Protocol................................... None
Passive Client Feature........................... Disabled
Peer-to-Peer Blocking Action..................... Disabled
Radio Policy..................................... All

--More-- or (q)uit
DTIM period for 802.11a radio.................... 1
DTIM period for 802.11b radio.................... 1
Radius Servers
   Authentication................................ Global Servers
   Accounting.................................... Global Servers
      Interim Update............................. Enabled
      Interim Update Interval.................... 0
      Framed IPv6 Acct AVP ...................... Prefix
   Dynamic Interface............................. Disabled
   Dynamic Interface Priority.................... wlan
Local EAP Authentication......................... Disabled
Radius NAI-Realm................................. Disabled
Mu-Mimo.......................................... Enabled
Security

   802.11 Authentication:........................ Open System
   FT Support.................................... Disabled
   Static WEP Keys............................... Disabled
   802.1X........................................ Disabled
   Wi-Fi Protected Access (WPA/WPA2)............. Disabled
   WAPI.......................................... Disabled
   Wi-Fi Direct policy configured................ Disabled
   EAP-Passthrough............................... Disabled

--More-- or (q)uit
   CKIP ......................................... Disabled
   Web Based Authentication...................... Disabled
   Web Authentication Timeout.................... 300
   Web-Passthrough............................... Disabled
   Mac-auth-server............................... 0.0.0.0
   Web-portal-server............................. 0.0.0.0
   Conditional Web Redirect...................... Disabled
   Splash-Page Web Redirect...................... Disabled
   Auto Anchor................................... Disabled
   FlexConnect Local Switching................... Enabled
   FlexConnect Central Association............... Disabled
   flexconnect Central Dhcp Flag................. Disabled
   flexconnect nat-pat Flag...................... Disabled
   flexconnect Dns Override Flag................. Disabled
   flexconnect PPPoE pass-through................ Disabled
   flexconnect local-switching IP-source-guar.... Disabled
   FlexConnect Vlan based Central Switching ..... Disabled
   FlexConnect Local Authentication.............. Disabled
   FlexConnect Learn IP Address.................. Enabled
   Client MFP.................................... Optional but inactive (WPA2 not configured)
   PMF........................................... Disabled
   PMF Association Comeback Time................. 1
   PMF SA Query RetryTimeout..................... 200

--More-- or (q)uit
   Tkip MIC Countermeasure Hold-down Timer....... 60
   Eap-params.................................... Not Applicable
AVC Visibilty.................................... Disabled
AVC Profile Name................................. None
Flow Monitor Name................................ None
Split Tunnel Configuration
    Split Tunnel................................. Disabled
Call Snooping.................................... Disabled
Roamed Call Re-Anchor Policy..................... Disabled
SIP CAC Fail Send-486-Busy Policy................ Enabled
SIP CAC Fail Send Dis-Association Policy......... Disabled
KTS based CAC Policy............................. Disabled
Assisted Roaming Prediction Optimization......... Disabled
802.11k Neighbor List............................ Disabled
802.11k Neighbor List Dual Band.................. Disabled
802.11v Directed Multicast Service............... Disabled
802.11v BSS Max Idle Service..................... Enabled
802.11v BSS Transition Service................... Disabled
802.11v BSS Transition Disassoc Imminent......... Disabled
802.11v BSS Transition Disassoc Timer............ 200
802.11v BSS Transition OpRoam Disassoc Timer..... 40
DMS DB is empty
Band Select...................................... Enabled

--More-- or (q)uit
Load Balancing................................... Client-Count Based
Multicast Buffer................................. Disabled
Universal Ap Admin............................... Disabled

 Mobility Anchor List
 WLAN ID     IP Address            Status                             Priority
 -------     ---------------       ------                             --------

802.11u........................................ Disabled

MSAP Services.................................. Disabled

Local Policy
----------------
Priority  Policy Name
--------  ---------------

Some of clients are complaining that they are being disconnected periodically from wireless. Any ideas? 

Thank you,

Catalin,

New Member

Hello ALL,

Hello ALL,

I am facing the same issue. Did anyone came up with any solution for it? I also have MAC binding enabled so all the MAC address that appear are genuine.

Thank you

New Member

Dear Catalin,

Dear Catalin,

I was unable to resolve the case, so went for Cisco TAC. After analyzing, Cisco found two DHCP servers were releasing IP simultaneously to its client. Only we confirmed after configuring DHCP snooping on core switch. After disabling one DHCP server, network became stable. Cisco recommended not to enable more than one DHCP server in our network. 

Cisco Employee

Do you have DHCP proxy

Do you have DHCP proxy enabled.If you do not have any "internal" DHCP scopes configured on the WLC, then try deselecting DHCP Proxy feature. For more information check the following thread

https://supportforums.cisco.com/discussion/11738046/dhcp-requests-starts-failing

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