Network not working after DHCP assigned IP address (XP)


I've just got a new PC up and running with Windows XP and I'm trying to get the network working. Currently we have a home network of three PCs connected to a Netgear router which in turn connects to a cable modem and then my ISP.

The three PCs all work find on the network but this fourth one won't. The problem is, it manages to contact the DHCP server and get assigned an IP address ok, which is valid and all the settings are correct. However once it's got its IP address, networking just doesn't work. I can't even ping to or from the machine to the router or any other PC.

I checked the network status, and it's sent packets, but not recieved any...

Any ideas? I can post any ipconfig stuff if necessary. I've tried a static IP address too, still nothing.
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try change the cable with one that its tested from one of the other PC's

IP address in the same DHCP Scope (is it valid)
ping the Loopback
ping the DNS server
ping the Default Gateway
ping the File server

first check the status of the cable the proceed
is there an Firewall running on the maschine ?
>it's sent packets, but not recieved any

Duplex mismatch or bad cable probably.
If replacing the cable doesn't work try setting the NIC to 100Mbit 1/2 duplex.
You might also have a bent pin in either the router or PC RJ45 sockets, or a bad NIC.
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jonnyvaughanAuthor Commented:
No firewall running. It's a fresh install of XP. (checked XP firewall too)

Tried changing the cable with a few others that are known to be working (besides, it manages to get the IP address correctly from the DHCP server in the first place) - still nothing.

IP address is valid (network is 192.168.0.*, assigned ip is - not conflicting with anything else either).

Can ping loopback and network ip (
Can't ping Default Gateway (the router,
Can't ping any other PC on the network
Can't ping DNS server
Can't ping (doesn't resolve)

Specifically assign the DNS server IPs in the TCP/IP DNS properties and this should resolve your're problem. Also, if you are on a workgroup  LAN then make sure your new box has the same workgroup config
jonnyvaughanAuthor Commented:
Tried assigned DNS servers statically and still nothing. The workgroup is set to what the others are 'mshome'.

Tried setting to half duplex, no joy.

The NIC is onboard (motherboard: Asus A78NX-VM - brand new mobo). If it were bent or broken pins and/or a broken NIC then I don't think it would get an IP address from the DHCP server properly?

OOOps, I keep thinking of Domain ENVs which is why I suggested statically assigning the DNS server IPs to your TCP/IP properties. You don't need this ifor the internal LAN but it does help for external if your having DNS problems.

In your case the fisrt place to look is the workgroup config.
Try uninstalling and re-installing your networking components from the add/remove programs applet in control panel and if that doesn't fix it, try a differnet NIC card. Maybe the one you have is a defect?
>If it were bent or broken pins and/or a broken NIC ...
You wouldn't think so, though when you see one counter incrementing and the other not, it's a shot.
DCHP works at the MAC level, so it seems an IP protocol issue.

Can you give up the output of ROUTE PRINT

Sometimes the quick fix is to remove all adaptors and protocols in safe mode, reboot, redetect the adaptor and install the protocols.

sorry mthibaul, i was typing as you posted
try inserting a NIC in the PCI slot and go from there !!
maybe take one you r sure working from one of the other mascines u have
jonnyvaughanAuthor Commented:
C:\Documents and Settings\Administrator>route print
Interface List
0x1 ........................... MS TCP Loopback interface
0x20002 ...01 23 45 67 89 ab ...... NVIDIA nForce MCP Networking Adapter - Packet Scheduler Miniport
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
        30        1        30        30        30        30        1
Default Gateway:
Persistent Routes:

C:\Documents and Settings\Administrator>ipconfig /all

Windows IP Configuration
        Host Name . . . . . . . . . . . . : fuzei
        Primary Dns Suffix  . . . . . . . :
        Node Type . . . . . . . . . . . . : Unknown
        IP Routing Enabled. . . . . . . . : Yes
        WINS Proxy Enabled. . . . . . . . : Yes

Ethernet adapter Local Area Connection 2:
        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : NVIDIA nForce MCP Networking Controller
        Physical Address. . . . . . . . . : 01-23-45-67-89-AB
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : Yes
        IP Address. . . . . . . . . . . . :
        Subnet Mask . . . . . . . . . . . :
        Default Gateway . . . . . . . . . :
        DHCP Server . . . . . . . . . . . :
        DNS Servers . . . . . . . . . . . :
        Lease Obtained. . . . . . . . . . : 16 November 2003 18:04:51
        Lease Expires . . . . . . . . . . : 19 January 2038 03:14:07

I'll try removing everything and reinstall networking, see what happens.
DNS Servers . . . . . . . . . . . :

That didn't come from DHCP??
everything else looks OK
do a

and post the output?
Getting your IP address from the DHCP server is a OSI layer 2 function. Ping is a ICMP function at layer 3. It is very possible to be able to get an address via DHCP but ping and other IP functions not work correctly. If you can ping the loopback address and the assigned IP address then the TCP/IP stack for that machine is probably functioning correctly.

You tried another, known good, cable. This leads me to believe that there may be a problem with the port on the router that this machine is connected too. Try another port that is known to be working correctly.

If that doesn't work you may need to install a network protocol anaylizer and look at what is happening on the network when you are trying to ping. You should install an anaylizer on both the new machine and one of the machines that is working.

There is a free anaylizer here
There is a learning curve to using an anaylizer, but it should point the way to the problem.
jonnyvaughanAuthor Commented:
ok I ran ethereal and checked out the packets it was sniffing. Seems like the XP pc keeps asking where the gateway is ( and the router replies giving the MAC address, but seems like the XP pc doesn't actually record this in anyway. Then the router asks everyone else to tell the XP pc which mac address it's at.

Also, none of the ICMP ping packets show up when I try to ping.. which i thought was odd.

Absolutely no idea what to do about that! I think I'll just have to buy a seperate NIC.
Have you tried simply swapping the patch cable to another port on your router, and doing a release/renew?
jonnyvaughanAuthor Commented:
Yeh I've tried that too.
Do you have any other networking-type services running on your XP?  You said you have the firewall disabled.  How about ICS, routing, any other services not necessary in a peer network?

Check to see what services you can safely disable.
DNS Servers . . . . . . . . . . . :

That didn't come from DHCP??
everything else looks OK
Comment from chicagoan

do a

and post the output?
If you've tried everything related to software, connection, cables, ports, the only alternative left is to replace the NIC with a known good one while re-installing all the network components!

What about the settings for your "Client for Microsoft" in LAN connection properties. Is it still set to Windows Locator?
Steve JenningsSr Manager Cloud Networking OpsCommented:
Im assuming you "dummied" the actual MAC address for some strange reason . . . or is your ethernet card actually 01-23-45-67-89-AB?

I don't think that's a valid OUI!
So what about the mac address and DNS servers and the output from


and post the output?

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chicagoan -
is that OUI as in Offline Usenet Interface or OUI as in Open User Interface or OUI as in the French for "yes?"
Steve JenningsSr Manager Cloud Networking OpsCommented:
. . . and are you from Chicago or (ready for rimshot) did your Hispanic wife leave you?

Sorry, I couldn't help it.

jonnyvaughanAuthor Commented:
Hmm yeh I just noticed that my MAC address for this NIC is rather... errm improbable let's say. I've not changed it, and that's what it seems to think it is.

Luckily though, these nForce2 boards allow you to change the MAC address and the one it's supposed to have is given on a sticker on the motherboard. I'll try getting that setting it back to what it should be - I really don't know what could have made it be that though!?

I'll try that first, then try the other things listed. But I'm assuming that 01:23:45:67:89:AB is a valid address anyway?
jonnyvaughanAuthor Commented:
Right ok, I found the solution to my problem, but only really thanks to SteveJ I think.

Check this thread out about the motherboard,

Seems like ASUS apparently ship this motherboard with an invalid MAC address. Luckily they print it on the mobo as I said before, so I'm gonna use XP to force that MAC address. I'll let you know if it works.

Organizational Unique Identifier -
Noboby is assigned to the OUI 01:23:45 and the improbability of it  ( along with your non-DHCP supplied DNS servers (I'm assuming your broadband router would supply itself) is very fishy and indicates someone or something has been mucking about with your network settings.

jonnyvaughanAuthor Commented:
As I suspected, all is well now, changed the MAC address via Device Manager - didn't even need a reboot and now all is well.

I can't actually believe that ASUS would ship their motherboards with invalid MAC addresses but print the correct one on a sticker on the motherboard. I've been tearing my hair out now for the last few days trying to get this fixed.

Thanks all for all your help, I'll decide who to give points to in a bit when I've re-read the posts.
Geez - that address is on the EPROM!??

Had a customer with a prom burner once who 'fixed' a bunch of token ring cards by copying a good one.
Took down the Chicago Board of Trade for two hours till I figured it out.
jonnyvaughanAuthor Commented:
Now if anyone can tell me how to force the address in Linux too - that would be much appreciated :)
Oh, OUI as in the first three octets of the MAC...  I get it.

If the first 3 octets of the MAC don't correspond to a device manufacturer then you have either messed with the preassigned MAC or someone else has...
I don't see how a nonstandard MAC address would have shipped with an ASUS mainboard.  They are a premium mainboard manufacturer, not a fringe mfr.  An onboard Ethernet interface EEPROM should be shipped with a valid MAC address that identifies the interface circuitry (asic or chipset or whatever) manufacturer.

jonnyvaughan - although the MAC *can* be reset by the user, it is advisable to leave the preassigned, registered MAC address alone, unless you are in a very insular, totally segregated network that does not access the Internet.  ARP has to be able to translate an IP address to a MAC address, and if you aren't using a valid set of MAC addresses, you're asking for trouble.

The only reason I can see that you'd have "bad" MAC addresses assigned is if you are converting from an IPX environment to an IP environment, and some admin somewhere along the line decided to assign MAC addresses to putz with the IPX LAN routing. since IPX node addresses are *Based* on the MAC address rather than how IP is *related* to MAC via ARP.
jonnyvaughanAuthor Commented:
ShineOn, check that link I posted to the forum and you'll see that ASUS do infact (probably by error) ship this motherboard without a valid MAC address.

Good job they print the one it should be on the motherboard though - and forcing it in Windows is the easy way to do it, or I can reflash the bios with the proper one.
Shame on ASUS for that.  I believe you, but I am still shocked that a "major" like ASUS - which also has a rep as a "premium" MB Mfr. - would do what you say they did.  

Sounds like they have to fix something in their QA, or they are not likely to maintain their "premium" status!
Steve JenningsSr Manager Cloud Networking OpsCommented:
These are valid locally administered MAC address ranges. No manufacturer should have a 2, 6, A, or E in the second position.


Glad it's working for you. In Linux, cant you just set the MAC address with ifconfig?

ifconfig eth0 hw ether <address>    (assuming of course that it's eht0).

Good luck,
Steve  - Dunno, I haven't gotten that deep into Linux yet.

I would be very VERY surprised, however, if you were unable to change the MAC address of an interface with Linux.  You can with just about all other OS-es.  

The thing is, you can usually rely on your hardware Mfr to give you a valid, unique MAC address... and not have to concern yourself with MAC address in the VAST majority of cases.
jonnyvaughanAuthor Commented:
Yeh, just read that ifconfig will do it, but resets it back on restart, so have to script that in somewhere to make sure it does it all the time.
jonnyvaughanAuthor Commented:
ok wasn't sure how to split this one, but gave it to chicagoan cos he did point out it wasn't valid, and points to stevej for pointing it out in the first place
Works for me...
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