id summary reporter owner description type status component version resolution keywords cc guest host 12300 NAT broken since VirtualBox 4.3 => Fixed in SVN wzyboy "I first reported this bug to Arch Linux, here is the original link: https://bugs.archlinux.org/task/37575 Since this bug exists in both OSE (compiled by Arch Linux community) and binary version (compiled by Oracle), IMHO this is a ""upstream bug"", so I re-post the bug report here. Here is a copy-and-paste of the original bug report: ---- Description: VirtualBox NAT function does not work any more after version 4.3. Instead, it just results in CPU 100% usage in host machine and the whole Qt interface becomes unreponsive. I've tested this on a 2011 HP laptop and a 2013 ThinkPad. The latter one was bought yesterday and had a fresh new installation of Arch Linux + VirtualBox. However, this problem exists regardless of host machine (different laptops) and guest machine (CentOS, Windows XP, Windows 8, etc). Additional info: * package version(s): community/virtualbox 4.3.0-3 * config and/or log files etc: VBox.log (Windows XP as guest machine) Steps to reproduce: 1. Fresh installation of Arch Linux. (Or use existing installation) 2. Install community/virtualbox, community/virtualbox-guest-iso, community/virtualbox-host-modules, aur/virtualbox-ext-oracle. 3. Install any guest OS. (CentOS, Windows XP, Windows 8) Enable ""NAT"" access. (This is default) 4. Launch guest machine and try to use DHCP to get networking address. 5. CPU 100% usage on host machine and the whole VirtualBox Qt interface become unresponsive. My (in vain) attempt to debug: 1. Try different guest OS -- not working. 2. Try different host machine -- not working. 3. Disable network interface for guest machine -- working but apprantly guest machine has no networking access. 3. Uncheck ""cable connected"" for guest machine -- working but apprantly guest machine has no networking access. 4. Use ""Bridged network"" instead of ""NAT"" for guest machine -- working 5. Try aur/virtualbox-bin -- not working I am not very sure if this is a Arch Linux bug or an upstream bug. The changelog of VirtualBox 4.3 *did* mention something about new ""NAT Network"" function. Maybe the new function broke something... VBox.log (80.4 KiB) ---- Please refer to the original bug report for VBox.log download and see also its comments for follow-up information. I've selected ""VirtualBox 4.3.0"" in ""Version"" field, but this bug still exists in 4.3.2." defect closed network/NAT VirtualBox 4.3.0 fixed NAT all Linux