DHCP assigning improper addresses for the VLAN

Posted on 2011-04-20
Last Modified: 2012-06-27
HP procurve 5406 at the core and HP 2848 at the edge, clients are all WinXP SP3, PXE clients are Altiris Deployment server clients

I wouldn't believe it if had not seen it with my own eyes. A recent rash of clients not getting DHCP addresses in a timely manner had me looking at one users PC. This PC is attached to a switch which is the 103 vlan, but it gets and an address from the 102 vlan! This is in both windows and PXE. Once I network boot and have Win PE loaded, DHCP fails to get an address.

I checked some more machines on the 103 vlan and on some I saw it get a vlan 102 address in PXE and then get a 103 vlan address in Windows.

In other instances I saw machines on the 103 vlan get vlan 102 addresses in PXE and fail to get addresses in windows. Upon trying ipconfig /renew on these same machines, I would receive an access denied error.

Last time I saw the access denied message, related to dhcp, I had a broadcast storm caused by someone connecting two ethernet ports in the same room.

Sort of scketchy details, but maybe someone out there has seen a similar scenario. The other vlans on the network are all working fine all the problems are on 102. I'm pretty sure I have something plugged in somewhere it shouldn't be, but have yet to find it.
Question by:rmstewart70
    LVL 61

    Assisted Solution

    are you sure cabling is correct?
    no leaks between subnets? (disable HP routing accelerator to make sure)
    LVL 39

    Accepted Solution

    The broadcast storm should not have happened if you had spanning tree enabled.

    First check that no one created a link between the 102/103 network using a patch cable or because the seperation is then lost.
    For HDCP at fist only Broadcasts are used..., and the first responding DHCP servers gets used...
    Check mac addresses in the mac table and see if vlan 102 macaddresses are visible in the vlan103, if so then there also is a port mentioned where it should be forwarded to...

    Assisted Solution

    After hours, you can disconnect or disable uplinks from individual wiring closets while testing CHCP to see which closet may have the cabling error.

    Featured Post

    Netscaler Common Configuration HowTo guides

    If you use NetScaler you will want to see these guides. The NetScaler HowTo Guides enable administrators to get NetScaler up and running by providing instructions for common configuration scenarios and some not so common ones.

    Join & Write a Comment

    Let’s list some of the technologies that enable smooth teleworking. 
    Don’t let your business fall victim to the coming apocalypse – use our Survival Guide for the Fax Apocalypse to identify the risks and signs of zombie fax activities at your business.
    Viewers will learn how to connect to a wireless network using the network security key. They will also learn how to access the IP address and DNS server for connections that must be done manually. After setting up a router, find the network security…
    After creating this article (, I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

    728 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    18 Experts available now in Live!

    Get 1:1 Help Now