If you receive:

<b>Netlogon Event ID 5701:

   The Netlogon service failed to update the domain trust list. The following
   error occurred: There are currently no logon servers to validate the logon
   request.</b>
you may have exhausted the NetBT datagram buffer.

Use regedt32 to navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetBT\Parameters

Add Value name MaxDgramBuffering as a type REG_DWORD and set the data value to 0x40000 (256K), using the Hex radix. The default for this Value Name is 0x20000 (128K) and the range is 0 - 0xFFFFFFFF.

NOTE: This error can be caused by a failing NIC or defective device driver.