When trying to boot with WDS and gets a TFTP TIMEOUT error, this article is for you.
In case this happens to anyone else (just happened to me after installing an update on the server and a couple of clients i rebuilt wouldnt boot as they just hung waiting for a tftp offer)
has happened to me after a windows update on server 2008 r2 (aparantly happens on straight 2008 as well) basically its due to having dns server on the same machine as wds dns pinches the ports the tftp service needs. This can leed to pcs not booting at all just sitting there failing to tftp if their boot order has lan set higher than hdd.
2008r2 fix
run regedit
go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Servic es\WDSServer\Parameters
Right-click UdpPortPolicy, and then click Modify.
In the Value data box, type 0, and then click OK.
On the File menu, click Exit to exit Registry Editor.
Restart the Windows Deployment Services service.
2008 r1
Click Start Collapse this imageExpand this image, click Administrative Tools, and then click Windows Deployment Services. If there is no server that is listed under the Servers node, right-click the Servers node, and then click Add Server to add the local computer.
In the navigation pane of the Windows Deployment Services MMC snap-in, expand the list of servers.
Right-click the server for Windows Deployment Services, and then click Properties.
Under Network, increase the UDP Port range. For example, if the current port range is 3,000 ports, increase the port range to 4,000 ports