Netgear WGT634U – WPA-PSK & DHCP

Symptom: DHCP does not assign IP’s when router is using WPA-PSK encryption. ‘Limited or no-connectivity’ messages appear after a ~2 min timeout once wireless client initiates connection. This problem is intermittent and more predominant when the router is under heavy load – experienced whilst playing a video over LAN whilst downloading torrents.

Related Symptom: Wireless traffic at a standstill – ie, trying to set IP’s manually without using DHCP results in timeouts. Gateway address (usually appears in ARP table but appears as invalid MAC addy 00-00-00-00-00-00.) Trying to set mac addy to IP of router statically still doesn’t work.


  • WPA-PSK connections to this router are threatened when router is under heavy load.
  • New connections will fail as DHCP will not work – once you’ve disconnected, its difficult for the card to reconnect.
  • This problem affects a variety of routers. Even the Linksys WRT54G isn’t safe. See this search for more info.

About this setup

Firmware Version:


  • WGT634U of course
  • DSL-302G w/DHCP in bridge mode connected to the Netgear’s Internet port.
  • All wireless cards below are affected
    • Intel 2100 B wireless mini-pci card
    • Netgear WG511U 108Mbps PCMCIA wireless card
    • Belkin 11Mbps PCI card
  • Lan connections from router to desktop, occasionally to the laptop (these are unaffected)

Operating Systems

  • Win XP Sp2
  • SUSE Linux 10

Known Workarounds

  • Use WEP based encryption and change your keys very frequently.
  • Powercycle all equipment (Netgears wizards / documentation indicate client computers should be rebooted when particular settings change – Why do they say this? What am I missing here that a regular enable/disable, clear ARP won’t fix?)
  • Use wired LAN to avoid encryption.
  • Modded firmware (OpenWGT, others?)

Stuff to Try

  • Initially (to replicate the problem and divide and conquer)
    1. Under WEP encryption, make all wireless clients use static addresses. (no dhcp)
    2. Switch to WPA encryption, clients still not using DCHP
    3. Continue using this sort of connection, operating the router under heavy load
    4. Hibernate PC, Awaken
    5. Should the connection drop and reconnect, check that traffic still runs thru that link
      1. If it doesn’t then the problem is not DHCP but WPA-PSK
      2. If traffic flows then DHCP w/WPA-PSK is the problem (have a feeling its not this one)
  • Other settings to try:
  • Long preamble – this is more to do with the initiating the connection
  • Slower speeds (11Mbps or lower?)
  • Reduce complex traffic as much as possible. Remove unnecessary protocols from the Network Connection
  • Switch on/off Adaptive Rate, Xtended Range
  • Issues about the router overheating due to power supply have been briefly mentioned in some forums (whirlpool, netgear’s support site). One user even mentioned that replacing the PSU with another routers one did the trick – will search for this one on request.
  • Use another device as the DHCP server (and maybe even the PPPoE to reduce load) – this would have to be the 302g moved to the Lan port
  • play with RTS/CTS fragmentation threshold (determines what type of wireless Collision Detection is used)
  • DHCP server on 302g could be interfering with server on WGT634U???

2 Replies to “Netgear WGT634U – WPA-PSK & DHCP”

  1. Ok, so I switched WPA-PSK on just a moment ago. So far, so good.

    Wireless Client settings are defaults, connecting at 108Mbps.

    Router settings:

    Basic Settings
    PPPoE connection.
    Idle timeout is 0

    Wireless Setup
    Channel 6
    Mode: Auto 108Mbps

    Workgroup for USB device sharing is different from default.
    There is no content filtering enabled however I did just set days to block to Monday, more of a paranoia setting

    Wireless Settings
    SSID Broadcast enabled
    Fragmentation Threshold and
    CTS/RTS Threshold at default.
    Preamble Mode: Auto
    108Mbps Settings
    Advanced 108Mbps Features Active
    Enabled Adaptive Radio(AR)
    Enabled eXtended Range(XR)

    No wireless MAC filtering

    AV Streaming is off, no port forwarding/triggering, no Dynamic DNS, static routes or remote management

    WAN setup
    Connect automatically as required
    Firewall still on
    MTU is 1400

    UPnP is on with default values

  2. Day 2
    Yesterday worked out fine. I was streaming a video on the LAN and also browsing websites and the router didn’t skip a beat. When I logged on this morning however, the cards were unable to obtain an IP addy. I switched on the Netgear smart assistant which uses its own settings over Windows to connect and the connection was successful. The MiniPCI in the laptop still wasn’t picking up the network so I removed the wireless network from the list and added it manually. After that, the card authenticated and everything was back to normal. I suspect but am not sure, that the card may get confused if other access points listed in windows have the same MAC address – for example, I renamed my SSID and still had the profile for the old SSID listed in the wireless networks tab of the wireless connections properties. I deleted this entry also which alivieted confusion.

    Because everything connected so well and I was using my laptop remotely I switched power management on MAX for the WG511U to see if this impacts network performance.

    Why remove the pre-existing windows networking settings?
    The consensus on the net is that when trying to connect to a WPA-PSK network, sometimes the supplicant software will advise that you are connected and trying to get you an IP via DHCP. In actual fact the pre-shared key is incorrect but for some reason the software shows this as you are connected to the network.

    So, we can assume that the wireless network profile thinks it knows how to connect and authenticate, but really doesn’t. Deleting this and starting again will help.

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