Category Archives: Linux

Centos 6 / 7 Openvpn forwarding not working

Seems Centos (thus RH) have changed the way things work slightly. Especially if you have multiple interfaces (NIC’s).

If your having problems with VPN not forwarding correctly, or your openVPN stopped working since updating from Centos 5, then this will most likely be what your looking for.

nano /etc/sysctl.conf

change

net.ipv4.conf.default.rp_filter = 1

to

net.ipv4.conf.default.rp_filter = 2

now reboot and enjoy.

BaDboD

Ubuntu 14.04 (Linux 64 bit) – No network, no USB 3 / USB 2

This mainly applies to 970 chipset mainboards, so your mileage may vary.

Symptom, no USB 3 , or Network, or USB 2 using Ubutnu 14.04 (actually from 12.04 up) 64 bit editions. As this is a kernel problem this should affect most 64 bit linux distros, not just Ubuntu.

There seems to be a problem with all recent 64 bit linux distros and 970 chipset mainboards.

There are 3 options.

1) Use a 32 bit distro.

2) In your BIOS enable IOMMU. This will fix your network and USB 2. You probably wont have USB 3 though ūüôĀ

3) Enable IOMMU in BIOS and add iommu=soft to your grub config. This gets rid of the stream of warnings you get at boot with IOMMU enabled in BIOS. USBB 3 should work too.

sudo nano /etc/default/grub

Change the line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash iommu=soft"

Then do

sudo update-grub

and reboot.

This should make the USB 2 and 3 work as well as networking.

Let me know what chipsets/mainboards this helped you with.

[updated]
Changed option 3 as noted by Anthony Barnett. Many hanks for the feedback Anthony.
[/updated]

BaDboD

Skype 4.1 , Ubuntu 12 – Distorted audio / sound

If your getting distortion when you open Skype, and/or distorted sound when Skype make a notification sound, read on …..

Go to Skype – Options – Sound Devices. Un-tick “Allow skype to automatically adjust my mixer levels”

If your STILL getting distortion open a command prompt and type

sudo nano /etc/pulse/default.pa

Add tsched=0 to the end of the line that reads ‘load-module module-udev-detect’ so it looks like…

load-module module-udev-detect tsched=0

Save (CTRL-X¬† –¬† Y¬† –¬† Enter)¬† and reboot.

Your good to go.

BaDboD

5.1 Realtek HD Audio, only front speakers working in Ubuntu 12 ?

Open a command prompt and enter

sudo alsamixer

then press F6 and select your sound card.

Use left/right arrow key to highlight ‘Channel’ at the bottom, then use up down key to select the number of speakers you have e.g. 5.1 so you should select 6. Press escape when done.

To restore this after a reboot type

sudo alsactl store

Your done.

Just make sure you have ‘5.1 out’ selected in the desktop volume control – settings for your audio card and you should now have full 5.1 sound.

Let me know if this works for you using other modes like 7.1 or just 4 speakers etc. It should.

Enjoy

BaDboD

Tails – New release

ok,ok, 2 weeks behind the times but, with all the new anti-privacy laws attempting to be sneaked in using the ruse of anti-piracy, you will need this. If not now, then very soon. Quite why it should be suspicious¬†behavior¬†to want to hide your credit card from¬†everyone¬†else when using it online I am not sure, but hey…. maybe you were actually purchasing that book with a bomb? Online too! Even more dangerous huh?

Tails 0.10.1 Numerous bug fixes and security enhancements.