DHCP issuing wrong IP address

  1. Hi guys.

    Here is an interesting one for you. For a few days now I noticed that 1 computer on this network has been issued the wrong IP address. It is a Windows XP Pro SP3 PC using a internal Realtek LAN adapter.

    Using DHCP issued from a 2wire ADSL router
    Default DHCP configuration
    IP Address Range ->
    Default Gateway

    However this computer has been issued with
    IP Address
    Default Gateway
    DHCP Server
    DNS Server

    Internet still works but network drive access doesn't.

    All computers are plugged into a NetGear 16 port network switch with 1 cable going to the 2Wire ADSL router.

    Everyone else on the network is correct and so was this PC up until last Thursday. The system was being used in the morning. Had a blackout and ever since this problem has occured.

    Trying a few things gives these results.
    Restarting the router and network switch - Made no change
    Restarting the PC - Made no change
    Disable Windows Firewall - Made no change
    Disable AVG AntiVirus - Made no change
    Disconnected LAN cable - Address issued was the default 169 auto config address
    Reconnected cable - Went back to
    Repaired Connection - Made no change
    IPCONFIG /RELEASE - Gave address
    IPCONFIG /RENEW - Gave address
    Used Setup Network Connection Wizard - Made no change

    There is only a single LAN adapter in the system and ICS is not enabled. Have got them out of trouble by using a static IP address and everything works fine however doesn't solve the DHCP problem.

    Anyone have any thoughts what is going on here?
  2. jobeard

    jobeard TS Ambassador Posts: 11,138   +985

    as dhcp ONLY serves to autoconf the client and you've setup static settings, actually you are DONE. The caveat of course is that you would like (I hope) to have one point of control from the DC side. Let's see ...

    one would hope the DNS would be on your DC or a public ISP; sure bizarre.
    (there's a remote chance of something else, but let's defer that discussion for now)

    Normally, the client BROADCASTS on x.x.x.255 port 68 and gets back
    the DHCP address and proceeds from there.

    === that leads to this issue Node Type = = =

    get Regedit
    go to the key
    set DhcpNodeType = 1 (if not found create a REG_DWORD and get the spelling and case as shown)
    set NodeType = 8 (same comment " " )

    Looks like the client has junk in the static config.
    Use View Network Connections (on the ailing system) right-click Local Lan->Properties
    scroll to Tcp/IP, click properties
    On the General Tab, click both Obtain xxx Automatically and ensure everything else is empty.
    Click the Advance button at the bottom
    * IP settings tab: shows DHCP Enabled; default gateway is empty [x] auto metric
    * DNS tab: everything empty and [x] Append primary & connection specific DNS suffixes
    * WINS tab: at the bottom; NetBios setting [x] Default
    .... you decide the WINS and Enable LMHOSTS lookup for your DC
    * Options tab: shows TCP/IP filtering; click properties button
    .... [x] all three Permit All

    Click OK three times to get back to the top, click close

    get a command prompt (start->run->cmd (using admin of course)
    • ipconfig /flushdns
    • net stop "dns client"
    • net start "dns client"
    (yes, keep the quotes)

    disconnect this system from the lan and wait 30 seconds and then reconnect
    wait another 30 seconds and rerun /ipconfig /all

    the Node Type should show up as Hybrid

    because it is on the WRONG subnet
  3. NotVeryWiseOne

    NotVeryWiseOne TS Rookie Topic Starter

    Ok I managed to fix one myself. jobeard I followed your advice with no success. Regarding the router, all 2wire ADSL routers I have come across uses this as the default address, not sure why, it just does.

    What I discovered was this particular PC was for some reason acting as a router in itself. There is only 1 adapter in the machine. As so the 2wire ADSL router doesn't like other routers and the result is an error in the web browser indicating router on router and had a resolve button. When pressed gave the PC the IP address of According to the router it had changed this PC to DMZPlus mode which isolates it from the rest of the network. Resetting this on the router gave the PC a normal IP again however gave the router on router error and the cycle starts again.

    To resolve it, again checked ICS and other settings even reset LAN adapter settings adn all was correct and still didn't work. Checked the firewall and that too looked correct however clicking the Reset Defaults button for the firewall fixed everything perfectly. All is now working well.

    I hope if someone comes across this in the future they can add this as something to try.

Similar Topics

Add your comment to this article

You need to be a member to leave a comment. Join thousands of tech enthusiasts and participate.
TechSpot Account You may also...