# Wireless IP Conflict



## pleebian (May 31, 2007)

I have a laptop running Vista Home Premium, which connects fine to every wireless network I've tried except at one particular local coffee house chain. At both locations I keep getting an IP address conflict error, and cannot get full connectivity. I believe that this has something to do with Vista because my old laptop, running XP, connected fine, and because no one else there ever has a problem connecting, and I've yet to find one running Vista.

I've tried repair and diagnose, ipconfig to manually reset the ip address, restarting the computer, reinstalling the drivers for the wireless card, giving myself a static ip, and all of the above with firewall on and off. Needless to say, the coffee house staff are not very knowledgeable about the workings of their network.

The network is one of those where you connect and then have to enter a password into a splash page that loads when you first open your browser. I can't load the page in either IE or Firefox.

Any ideas about what might be causing this? Any other information I can give that would help? 

Thanks in advance.


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## TerryNet (Mar 23, 2005)

An ipconfig /all may help. Could post one now for your home connection. But then might need one for when you are trying to connect at the problem place; if you could also get an ipconfig /all from a PC that does connect there, that would be great.


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## pleebian (May 31, 2007)

This is also on a wireless connection, although obviously a working one:

Microsoft Windows [Version 6.0.6000]
Copyright (c) 2006 Microsoft Corporation. All rights reserved.

C:\Users\Andrew\>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : Andrew
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : hsd1.mi.comcast.net.

Wireless LAN adapter Wireless Network Connection:

Connection-specific DNS Suffix . : hsd1.mi.comcast.net.
Description . . . . . . . . . . . : Intel(R) PRO/Wireless 3945ABG Network Con
nection
Physical Address. . . . . . . . . : 00-19-D2-86-68-4D
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::b046:7d44:288c:51b9%13(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.0.175(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Friday, June 01, 2007 6:37:55 AM
Lease Expires . . . . . . . . . . : Friday, June 08, 2007 6:37:54 AM
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.1
DHCPv6 IAID . . . . . . . . . . . : 151001554
DNS Servers . . . . . . . . . . . : 192.168.0.1
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Local Area Connection:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . : hsd1.mi.comcast.net.
Description . . . . . . . . . . . : Intel(R) PRO/100 VE Network Connection
Physical Address. . . . . . . . . : 00-16-36-FC-36-EA
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 10:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 02-00-54-55-4E-01
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2001:0:4136:e37e:896:1eba:3f57:ff50(Prefe
rred)
Link-local IPv6 Address . . . . . : fe80::896:1eba:3f57:ff50%9(Preferred)
Default Gateway . . . . . . . . . : ::
NetBIOS over Tcpip. . . . . . . . : Disabled

Tunnel adapter Local Area Connection* 12:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . : hsd1.mi.comcast.net.
Description . . . . . . . . . . . : isatap.hsd1.mi.comcast.net.
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Also, here's the text from the System event log for Dhcp-Client while I was at the problem site:

Your computer has detected that the IP address 172.16.31.213 for the Network Card with network address 0019D286684D is already in use on the network. Your computer will automatically attempt to obtain a different address.

That message is repeated in the event log about every 11 seconds, with various 172.16.31.xxx addresses. In between there is typically two messages labeled Time-Service which read:

NtpClient was unable to set a manual peer to use as a time source because of DNS resolution error on 'time.windows.com,0x1'. NtpClient will try again in 15 minutes and double the reattempt interval thereafter. The error was: No such host is known. (0x80072AF9)


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## JohnWill (Oct 19, 2002)

A different network IPCONFIG obviously has little utility in analyzing this issue. We need to know the environment you're working in when you have the problem.

Since this is restricted to one location, I'm guessing something about the applet that logs you in is not Vista compatible, so it keeps trying to connect using new IP addresses. This is just a guess based on very limited information...


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## pleebian (May 31, 2007)

Here's ipconfig /all from the coffee shop where I have the problem. The thing that jumps out at me is the lack of Dns suffix and gateway, not that I know what to do about it.

Microsoft Windows [Version 6.0.6000]
Copyright (c) 2006 Microsoft Corporation. All rights reserved.

C:\Users\Andrewr>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : Andrew
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Wireless LAN adapter Wireless Network Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) PRO/Wireless 3945ABG Network Con
nection
Physical Address. . . . . . . . . : 00-19-D2-86-68-4D
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::b046:7d44:288c:51b9%13(Preferred)
Autoconfiguration IPv4 Address. . : 169.254.81.185(Tentative)
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :
DHCPv6 IAID . . . . . . . . . . . : 151001554
DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Local Area Connection:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . : hsd1.mi.comcast.net.
Description . . . . . . . . . . . : Intel(R) PRO/100 VE Network Connection
Physical Address. . . . . . . . . : 00-16-36-FC-36-EA
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 6:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft ISATAP Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 10:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 02-00-54-55-4E-01
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 12:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : isatap.hsd1.mi.comcast.net.
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes


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## TerryNet (Mar 23, 2005)

See if your laptop manufacturer has an updated driver for the Intel adapter. Also, if you haven't been using the Intel utility try it.


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## evarlast (Aug 21, 2007)

Pleebian,

Could it be Espresso Royale in Ann Arbor MI?

Check your event log in Vista. My guess is you will see a large number of 1005 DHCP errors. Read the text.

http://technet2.microsoft.com/windo...ce51094d-c3f0-4b14-a5be-7520092de5d81033.mspx

It turns out that MS's DHCP client tries to be smart, but is really stupid. It REFUSES to assign an IP that is in use. But some Network Access Points put all addresses in use until they are DHCP assigned. This seems to be the case at the place you mention.

I have not yet found a fix to this. Can anyone help me find a fix?


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## JohnWill (Oct 19, 2002)

This makes no sense. If that were the case, DHCP could never get an address. Remember how DHCP works.

Client sends a broadcast request asking for an IP address assignment.
DHCP server sends a response with an IP address lease or a NAK if the lease is refused.
Client uses the IP address supplied.

The client has no knowledge of what IP addresses are in use, that's the sole responsibility of the DHCP server.

AFAIK, every DHCP server works that way, it's how the standard is defined.

RFC 2131 Dynamic Host Configuration Protocol


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## evarlast (Aug 21, 2007)

you are right, it doesn't make sense.

But that doesn't mean it doesn't exist.

This is DIRECTLY from my Vista Event Log:

Your computer has detected that the IP address 172.16.31.178 for the Network Card with network address 001B77446604 is already in use on the network. Your computer will automatically attempt to obtain a different address.

or in XML for completeness:
- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
<Provider Name="Microsoft-Windows-Dhcp-Client" Guid="{15A7A4F8-0072-4EAB-ABAD-F98A4D666AED}" EventSourceName="Dhcp" /> 
<EventID Qualifiers="0">1005</EventID> 
<Version>0</Version> 
<Level>3</Level> 
<Task>0</Task> 
<Opcode>0</Opcode> 
<Keywords>0x80000000000000</Keywords> 
<TimeCreated SystemTime="2007-08-21T15:05:29.000Z" /> 
<EventRecordID>27634</EventRecordID> 
<Correlation /> 
<Execution ProcessID="0" ThreadID="0" /> 
<Channel>System</Channel> 
<Computer>theknife</Computer> 
<Security /> 
</System>
- <EventData>
172.16.31.178 
001B77446604 
</EventData>
</Event>

So it DOES indeed check that an IP is in use.

Now the issue is how to make Vista STOP doing this when you are trying to connect to certain access points.

What is worse is that you cannot even disable DHCP and give yourself a static address. Vista will still detect the address conflict and use an automatic ip (APIPA)

My question is: How to turn off vista's ip address conflict detection?


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## JohnWill (Oct 19, 2002)

This is a symptom of the DHCP server getting reset and the workstation not being rebooted. Since the DHCP server lost all of it's history of what IP addresses were assigned, it started over from the top of the list. This is a VERY COMMON occurrence with SOHO routers. Somewhere within range of that AP is a workstation that is still using an IP address that the DHCP server is trying to assign. 

Another common reason for this is that someone has assigned a static IP address in the range of the DHCP server.

Since it's at a coffee house, you don't have much control over sorting out the issue. However, I can assure you that any DHCP server works just like the description I posted in 
RFC 2131 Dynamic Host Configuration Protocol, otherwise machines trying to connect would not know what to do.


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## MrDasher (Aug 31, 2007)

Well, definitely a Vista "enhancement". 
Sitting at coffee shop, my XP laptop connects no problem, my Vista laptop not a chance. It gets dhcp address then discards it thinking it's already in use even though I'm the last one here. Gets an APIPA sddress all the time even when a manual IP is set. Event log fills up with 1005 events from source DHCP-Client (basic IP conflict message).

Have changed some registry entries as per some MS articles and some posts:
DhcpConnDisableBcastFlagToggle, etc... It worked once for several hours then never again.

Any proposed solution from MS??? or anyone else for that matter.

Thanks.


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## JohnWill (Oct 19, 2002)

Did you try this: Vista Can't obtain IP address from some DHCP Servers


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## MrDasher (Aug 31, 2007)

JohnWill said:


> Did you try this: Vista Can't obtain IP address from some DHCP Servers


I have tried the instructions in that MS article. At first it didn't work, then it did, then it didn't again. Thus I have no idea if it really makes a difference or not.
Now I'm back at home and it wouldn't connect to my own network. I deleted the wireless profile and recreated it but this did not resolve the connectivity issue.
The diagnostic utilized in Vista is useless in either cases, and there's little to nothing in any of the log files.

Since this is a major issue, I'm thinking of rolling back to XP...

Any other sugestions?


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