"unable to contact DHCP server" troubles

Hello everyone,

After days of lots of trial & error and trying various fixes found on the internet, I still can't get my wireless LAN to work properly in SP2.

I have one host (XP Pro SP2) and one client (XP Home SP2), connected wirelessly via ad-hoc. The host PC is connected to the internet with a cable modem and has a wireless NIC for the WLAN. The main problem is that the laptop client can't aquire a valid IP address and uses a 169.254.x.x address. When doing ipconfig /release ipconfig /renew on the client, it times out with the "unable to contact your dhcp server" error.

Now, at one point, I somehow had managed to establish a connection to the host (right after running the network setup wizzard), I could use file sharing, but not surf the net. The problem was that the client couldn't resolve any domain names, since I *could* surf the net by entering IP addresses instead of domain names (http://207.46.250.119 instead of www.microsoft.com etc.). I thought maybe /releasing and then /renewing would fix this DNS issue, but no - I got the same "unable to contact DHCP server" error again!

I applied both fixes found in this forum's sticky on both the laptop and the PC, to no avail. ICS and file sharing did work when both machines had SP1. All software firewalls are off. The DHCP and DNS services are running on both machines.

In case the experts would like to see my ipconfigs:

HOST



Windows IP Configuration

Host Name . . . . . . . . . . . . : barton
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : Yes
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Wireless Network Connection 2:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Marvell Libertas 802.11b/g Wireless SoftAP
Physical Address. . . . . . . . . : 00-11-2F-43-A1-F6
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.0.1
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Motorola SURFboard 4200 USB Cable Modem
Physical Address. . . . . . . . . : 00-08-0E-8A-9E-69
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 217.147.36.x
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 217.147.36.254
DHCP Server . . . . . . . . . . . : 217.147.34.20
DNS Servers . . . . . . . . . . . : 217.147.34.13
217.147.40.2
Lease Obtained. . . . . . . . . . : Friday, October 29, 2004 22:57:43
Lease Expires . . . . . . . . . . : Saturday, October 30, 2004 00:57:43



CLIENT (using STATIC config (read last paragraph))

Windows IP Configuration
Host Name . . . . . . . . . . . . : HP_MOB
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Mixed
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:
Media State . . . . . . . . . . . : Media disconnected
Description . . . . . . . . . . . : National Semiconductor Corp. DP83815/816 10/100 MacPhyter PCI Adapter
Physical Address. . . . . . . . . : 00-0D-9D-5B-D7-8E

Ethernet adapter Wireless Network Connection:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Broadcom 802.11b
Physical Address. . . . . . . . . : 00-90-4B-42-C9-89
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.0.3
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.1
DNS Servers . . . . . . . . . . . : 192.168.0.1
217.147.34.13


By the way, setting the client to use a static configuration and entering 192.168.0.1 as the DNS Server gives me basic connectivity (can ping each other), but that's it, DNS resolving doesn't work and I can't use file sharing. Now if I enter my ISP's DNS server on the client machine, I can surf the net on it and DNS resolving works, but file sharing still doesn't.

I would be very grateful if you could help me out! I'm starting to lose my nerves with this
Thanks!

 

Have you set up your Ad Hoc structure like This article describes? I'm really surprised that ICS DHCP can't assign address values correctly for you.

As to the local network / file sharing issues, there seem to have been some things you could play fast and loose with pre-SP2 that quit working with the tighter security that came with SP2. Since all the SP2 security is designed with TCP/IP in mind, you might do well at this point to
- install NetBEUI on both PCs
- if you are logging onto both PCs, both are in the same workgroup (and no spaces in the workgroup name), each has a different PC name (no spaces in the PC name) then you should have your local file sharing back and not really need to figure out what was "broken" by SP2.
- I much prefer to disable the guest accounts on both PCs and either use the same username/password to log on to each or to put both username/password accounts on both PCs.
- Since XP-home isn't real bright when it comes to some networking pieces, you will need to have Simple File Sharing enabled on the XP-pro PC to make things as smooth as possible since XP-home only does that sort of file sharing.

Since NetBEUI does not use TCP/IP, you can turn on firewalls on your PCs without any problems.

Since NetBEUI is non-routable, if you change the bindings on your network cards so that File & Printer Sharing is bound to NetBEUI and unbound from TCP/IP, you will have further protected your local network from intrusion.

 

Thanks for your prompt reply Newt, very appreciated

Yes, I did configure my ad-hoc WLAN as described in that article. And after reconfiguring everything, DHCP still didn't work.

I installed NetBEUI on all machines successfully and now I can share files & printers, thanks for that tip
So now I'm running a static WLAN, but at least everything seems to work...
Thanks for the help

 

I may be missing something here (a feature of ICS that I am missing perhaps), but as far a I can see you do not have either a DNS server or a DHCP server on your wireless network. I think you are confusing clients with services.

By enabling DNS and DHCP on XP Pro/Home computers, what you are doing is setting up their client components. So you have set up the client applications on both computers, but unfortunately clients won't talk to clients. A basic rule of TCP/IP networking is that comminication is from client to service, or service to client; never client to client nor service to service.

As far as I can see you should use static IPs or rely on the automatic IP assignment in the 169.254.x.x address space (in which case both wireless connections need to use this IP address space). You cannot use DHCP, because you do not have a DHCP server on your wireless network. However, this should not be a problem with only two computers. If you get more, I'd suggest investing in an Wireless Access point to manage the wireless network. These usually have a DHCP service. However, with only two computers, ad hoc and static IPs is fine.

The Client PC set up is right, except that the DNS should not point at the other PC. That is, DNS should not be set to 192.168.0.1. Instead this address should be set to the same IP address used on the other PC. That is 217.147.34.13.

This incorrect DNS setting accounts for your inability to connect to the internet by DNS name. Basically every time you tried to connect to an internet address, the client PC was asking the other PC for the address, but it would not replay because it doesn't have a DNS service running. Therefore your client PC could not resolve the address.

With XP you'll get other local network connection problems if DNS is not set up correctly. In this case, installing netBEUI forced the systems to use NetBIOS names locally and therefore over-rode the DNS naming system and ineligantly (in my opinion) fixed the problem.

 

If Windows' ICS didn't have a built-in DHCP/DNS service then it would kind of lose it's purpose wouldn't it?

Also, everything worked perfectly (host assigning IPs, DNS working fine) with SP1 and, as far as I know, IPs of the 169.254.x.x range use a subnet of 255.255.0.0 which is not suitable for ICS, but I may be wrong.

Actually there is a total of three computers on the network, it's just that the third one (a laptop) is not available most of the time, but yesterday it was and I had both clients on the net with static configs and NetBEUI running the file sharing. I know that an AP would probably run things more flawlessly and strengthen the WLAN signal as now it's pretty weak, but I thought I'd just save the money and try it this way..

As for the DNS server being 192.168.0.1, MS actually tells you to use that for the client PCs when using a static config. Using your ISP's DNS is the last option when 192.168.0.1 doesn't work out.

I agree with you that installing NetBEUI was an inelegant solution, but nothing else worked.

Speaking of nothing working... I am not able to establish a connection once again, both computers can't see each other I try to configure a new network on the host, but the client can't see it after countless refreshes of the available network list, and vice versa

Any more ideas, Reggie and Newt? Thanks for both of your input so far

 

Certainly NetBEUI is not an elegant solution but if it does work, not only do you have a workaround (albeit sorta kludgy) but you also have confirmation that your network is functional.

If your File & Printer Sharing bindings are to NetBEUI only, you have also added a layer of protection.

ReggieB - XP's ICS (and earlier versions I think) does have the host PC acting as DHCP and DNS server for the LAN.

Good information on XP & ICS Here including a couple of things that were new to me. I do think that an all-XP ICS LAN can use other IP address ranges but not positive and have zero first hand experience with ICS. None planned either.

"Configuring the Default Gateway, DNS, and Host Name
ICS clients must be configured to use the ICS host for their default gateway and DNS server. This causes the ICS host to act as a gateway to the Internet for the client, and takes care of resolving names for the client. With Windows XP ICS, the internal interface that is used by ICS always has an address of 192.168.0.1. Therefore, you must configure the static clients to use this address for Domain Name System (DNS) and Dynamic Host Configuration Protocol (DHCP) requests.

Windows XP ICS also always uses a domain name of MSHOME.NET. Therefore, to specify a fully qualified host name for a client, you must use the client computer name followed by ".MSHOME.NET ". For example, "COMPUTER1.MSHOME.NET" is the fully qualified name of an internal client with a name of COMPUTER1. "

Justas G - I'm not at all sure what you meant with the above. Explain using more words?

 

It looks like I was wrong. Thank you Newt for correcting me.

 

ICS is bizarre and counter-intuitive for folks who have been doing 'regular' networking for any length of time. But it usually does work and always is free.