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Not getting DHCP address via WAP

Posted on 2009-03-31
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Last Modified: 2013-12-27
I'm having trouble with wireless clients getting an ip address via our wireless access point(s).  We have two Cisco Aironet 1200's and a Linksys WAP that are broadcasting a great signal, our laptops connect to the boxes, but then fail to get a DHCP address.  The laptop tries for about 30 seconds and then times out, I get either and ip of 0.0.0.0 or a 169 address.  If you plug any of these laptops in via a cable they get and ip and can browse the inter/intranet without any problem at all.
So far I have moved DHCP to another server, turned off AV, tried different access points, tried different ports on the switches, tried different WEP keys all to no avail.
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Question by:emeschke
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by:Quori
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Can you provide the AP config please?

What you can do is try and configure the ip helper-address to be your DHCP server.
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by:cosmicfox
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usually when you have DHCP problems with Wireless it could be a problem with the wireless setup. If you connect to the wireless and put in a static ip that is on the wireless lan and you are unable to ping or get to the dhcp server then the wireless setup could be wrong on the client. It could be as simple as fat fingered password.
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by:Multipath
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Do you have DHCP helpers on your switch, have you set up separate vlans for the wireless?
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by:emeschke
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I have not setup separate vlans for wireless.  AP configuration is 128 bit WEP with SSID being broadcast, nothing complicated at all.
I have tried changing to 64 bit wep as it is a bit easier to type in the password.  This did not seem to help at all though.
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by:Multipath
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It is most likely not your encryption but your vlan configuration.  Do you have the DHCP helpers in the configuration of the vlan (this is a cisco thing, not sure what switches you have).
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by:emeschke
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I do not have the DHCP helpers in the vlan config (I have Cisco switches as well).  The reason I tried the Linksys box in the configuration was to rule out the Cisco APs.
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by:KvChaos
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Switch(or at least a cisco switch) will drop DHCP broadcast. Hence, as long as your workstations and DHCP server is seperated by a switch, ip helper setting on the switch is necessary.
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by:emeschke
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Why has this worked for 4 years on those switches and now all of a sudden it doesn't?
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by:Multipath
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Config change or maybe ios upgrade most likely
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by:KvChaos
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I would say network change, because i believe switch blocking dhcp broadcast is not a recent thing..
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by:emeschke
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The two things that changed from last week to this week are:
1. We switch external DNS servers from Choice One to Network Solutions
2. We upgraded from Trend Office Scan 7.3 to Office Scan 8.0
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by:Multipath
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Can you paste the the output of a sh ver
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by:KvChaos
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To troubleshoot if it's a trendmicro problem, try to get into safemode with networking and see if problem persists?
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by:emeschke
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Here is the Show Ver

Cisco Internetwork Operating System Software
IOS (tm) C1200 Software (C1200-K9W7-M), Version 12.3(2)JA, RELEASE SOFTWARE (fc2
)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Mon 08-Nov-04 12:47 by ccai
Image text-base: 0x00003000, data-base: 0x0064854C

ROM: Bootstrap program is C1200 boot loader
BOOTLDR: C1200 Boot Loader (C1200-BOOT-M) Version 12.2(8)JA, EARLY DEPLOYMENT RE
LEASE SOFTWARE (fc1)

BRAP uptime is 6 days, 20 hours, 27 minutes
System returned to ROM by power-on
System image file is "flash:/c1200-k9w7-mx.123-2.JA/c1200-k9w7-mx.123-2.JA"


This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

cisco AIR-AP1231G-A-K9     (PowerPC405GP) processor (revision B0) with 14326K/20
48K bytes of memory.
Processor board ID FOC08490R04
PowerPC405GP CPU at 196Mhz, revision number 0x0145
Last reset from power-on
Bridging software.
1 FastEthernet/IEEE 802.3 interface(s)
1 802.11 Radio(s)

32K bytes of flash-simulated non-volatile configuration memory.
Base ethernet MAC Address: 00:12:D9:68:88:95
Part Number                          : 73-8704-08
PCA Assembly Number                  : 800-23211-09
PCA Revision Number                  : A0
PCB Serial Number                    : FOC08490R04
Top Assembly Part Number             : 800-23304-08
Top Assembly Serial Number           : FTX0902J51P
Top Revision Number                  : A0
Product/Model Number                 : AIR-AP1231G-A-K9

Configuration register is 0xF
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Author Comment

by:emeschke
Comment Utility
Here is the Config...

Using 1694 out of 32768 bytes
!
version 12.3
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname BRAP
!
enable secret 5 $1$f0Xc$GPdQ8GhoAQjGRRx1vx/Sa.
!
username Cisco password 7 13261E020803
ip subnet-zero
!
no aaa new-model
!
!
bridge irb
!
!
interface Dot11Radio0
 no ip address
 no ip route-cache
 !
 encryption key 1 size 128bit 7 6D5F29331C0A2F2D2A1823706C91 transmit-key
 encryption mode wep mandatory
 !
 ssid Ghost.COM
    authentication open
    guest-mode
 !
 short-slot-time
 speed basic-1.0 basic-2.0 basic-5.5 6.0 9.0 basic-11.0 12.0 18.0 24.0 36.0 48.0
 54.0
 station-role root
 no cdp enable
 bridge-group 1
 bridge-group 1 subscriber-loop-control
 bridge-group 1 block-unknown-source
 no bridge-group 1 source-learning
 no bridge-group 1 unicast-flooding
 bridge-group 1 spanning-disabled
!
interface FastEthernet0
 no ip address
 no ip route-cache
 duplex auto
 speed auto
 bridge-group 1
 no bridge-group 1 source-learning
 bridge-group 1 spanning-disabled
!
interface BVI1
 ip address 192.168.3.177 255.255.255.0
 no ip route-cache
!
ip default-gateway 192.168.3.1
ip http server
no ip http secure-server
ip http help-path http://www.cisco.com/warp/public/779/smbiz/prodconfig/help/eag
ip radius source-interface BVI1
logging snmp-trap emergencies
logging snmp-trap alerts
logging snmp-trap critical
logging snmp-trap errors
logging snmp-trap warnings
bridge 1 route ip
!
!
!
line con 0
 transport preferred all
 transport output all
line vty 0 4
 login local
 transport preferred all
 transport input all
 transport output all
line vty 5 15
 login
 transport preferred all
 transport input all
 transport output all
!
end
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Accepted Solution

by:
emeschke earned 0 total points
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Discovered that secondary domain controller was broadcasting a network storm from the WINS service.  After a stop and restart of the WINS service the storm ended.
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