Asymmetric networking using Linux
The idea is simple, two subnets (separate networks) and then route packets from one to the other. The environment, however, is not symmetric. We wanted to contact a node on the other subnet and we could see the packets travelling over the switch to the router back through another switch to the node, but the node itself refused to reply.
Each node has two NICs and each NIC is connected to a separate network. If you try to connect or ping one node from another, Linux is smart enough to go directly over the NIC with the right network. If a NIC should ever fail, the failover is that the packets are then routed up one network to the router then over to the other network.
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Wireless BCM4312 3.2 kernel
Since there is an Ubuntu package ‘firmware-b43-lpphy-installer’ which is up to date and will work against the 3.0 kernel, my earlier posts are obsolete. If you are not running Ubuntu, then you will still need to reference my post.
The latest 3.2 Linux kernel however has a few ABI changes, most notably in the network stack which effects the Broadcom’s wl module. Most notably is: .ndo_set_multicast_list which was replaced with .ndo_set_rx_mode.
Build environments using chroot
The need was simple enough: make deb packages from source for multiple architectures on the same system. This needed to be done without the overhead of a virtual machine and without using something like launchpad.
I’ve used chroot in the past and it seemed like a perfect fit for the problem. The idea is to have at least two chroot-able directories with the bare essentials from Ubuntu Natty (10.04) to compile and build deb packages.
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Skype on Ubuntu 11.10 (Oneiric Ocelot)
If you upgrade to Ubuntu 11.10 on a 64-bit platform and try to run skype then you will likely get this error:
skype: error while loading shared libraries: libXss.so.1: cannot open shared object file: No such file or directory
This is because libxss1 and a few other libraries have been removed from ia32-libs package.
You will need to enable multiarch and install the extra 32 bit libraries by hand:
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Ubuntu 11.04 Natty with fglrx and 2.6.39
Natty (11.04) users can finally get fglrx playing nicely together with X.org 1.10. We can also make the latest driver work well with the 2.6.39 kernel.
Custom build procedure:
- Install the latest 2.6.39 kernel revision from Ubuntu Mainline or install the PPA.
- Download 64-bit 11.4.
- Extract the files from the package:
sh ./ati-driver-installer-11-4-x86.x86_64.run --extract ati - For 2.6.39 support, download this extra patch: 2.6.39_bkl.patch
- Check for Big Kernel Lock usage:
cat /lib/modules/`uname -r`/build/.config | grep -c CONFIG_BKL=y
If the result of this command is 0, then download no_bkl.patch as well. - then apply them:
cd ati; for i in ../*.patch; do patch -p1 < $i; done - Build your new ati/fglrx deb packages:
./ati-installer.sh 8.841 --buildpkg Ubuntu/natty - Install our newly created deb packages:
sudo dpkg -i ../fglrx*.deb - If your /etc/X11/xorg.conf is missing you will need to run:
sudo aticonfig --initial
and then reboot.
That newly created package should work for the entire 2.6.39 series.
