Posts Tagged ‘modprobe’

Play Midis on Linux / Make Linux MIDI Ready for the Future – Enable embedded MIDI music to play in a Browser, Play MIDIs with VLC and howto enjoy Midis in Text Console

Wednesday, October 4th, 2017

how-to-play-midi-on-gnu-linux-in-graphic-environment-console-and-browser-midi-synthesizer-and-linux-tux-together

 

Play Midis on Linux or Make Linux MIDI Ready for the Future – Enable embedded MIDI music to play in a Browser, Play MIDIs with VLC and howto enjoy Midis in Text Console HOWTO

 

Playing MIDI has been quite a lot of fun historically,

if you grow up in the days when personal computers were still young and the Sound Blaster was a luxury, before the raise of Mp3 music format, you have certainly enjoyed the beeping of PC Speaker and later on during 386 and 486 / 586 computers the enjoyment of playing tracked music such as S3M and MOD,

in that good days playing MIDI music was the only alternative for PC maniacs who doesn't own a CD Drive (which itself) was another luxury and even thouse who had a CD ROM device, were mainly playing music in CD audio format (.CDA).
Anyhow MIDI was a cheap and a CPU unintensive way to listen to equivalent of favourite popular Audio Songs and for those who still remember many of the songs were recreated in MIDI format, just with a number of synthesized instruments without any voice (as MIDI is usually).

The same was true also for the good old days of raise of Mobile Phones, when polyphonic was a standard as CPU power was low MIDI was a perfect substitute for the CPU heavy Encoded MP3s / OGG and other formats that required a modern for that time Intel CPU running in 50+ Mhz usually 100 / 166Mhz was perfect for the days to play Mp3 but still even on that PCs we listened to Midi songs.

Therefore if you're one of those people like me who still enjoy to play some Midi Music in the year 2017 and feel a bit like Back into the Future movie and a Free Software fan and user, especially if you're a novice GNU  / Linux Free Software user, you will be unpleasently surprised that most today's default Linux distributions doesn't have an easy way to play Midi music format out of the box right after install.

Hence below article aims to give you an understanding on

How you can play Midi Music on GNU / Linux Operating System

First, lets Prepare to load necessery Linux kernel modules to make sure MIDI can be played by soundcard:

In /etc/modules make sure you have the following list of modules loaded:
 

linux-desktop:~# cat /etc/modules
3c59x
snd-emu10k1
snd-pcm-oss
snd-mixer-oss
snd-seq-oss

!Note the modules are working as of time of writting and in time can change to some other modules, depending on how the development of ALSA (Advanced Linux Sound Architecture) goes, and if the developers decide to rename the upmentioned modules

If you just have added the modules to /etc/modules with vim / nano to reload modules into the Linux kernel run:

 

linux-desktop:~# modprobe -a


Secondly, Installing a whole bunch of MIDI music related program tools can be achieved in Debian by installing the multimedia-midi package, e.g.:

 

linux-desktop:~# apt-get install –yes multimedia-midi

 

1. Playing Midi in Graphical environment with a double click using VLC


How to make MIDI easy listanable in Linux graphical environment like GNOME / KDE / XFCE desktop ?

 

If you want to make Midi music execution sa easy as  just clicking on the .MIDI file format on Linux you can do that with a midi extension available for VLC (Video Lan Client) Universal Multi Platform Media Player player

To install it on Debian Ubuntu GNU / Linux
 

# apt-get install –yes vlc-plugin-fluidsynth

 

Необходимо е да се изтеглят 6754 B архиви.
След тази операция ще бъде използвано 35,8 kB допълнително дисково пространство.
Изт:1 http://deb.debian.org/debian stretch/main amd64 vlc-plugin-fluidsynth amd64 2.2.6-1~deb9u1 [6754 B]
Изтеглени 6754 B за 0с (33,6 kB/сек)           
Selecting previously unselected package vlc-plugin-fluidsynth:amd64.
(Reading database … 382976 files and directories currently installed.)
Preparing to unpack …/vlc-plugin-fluidsynth_2.2.6-1~deb9u1_amd64.deb …
Unpacking vlc-plugin-fluidsynth:amd64 (2.2.6-1~deb9u1) …
Setting up vlc-plugin-fluidsynth:amd64 (2.2.6-1~deb9u1) …
Processing triggers for libvlc-bin:amd64 (2.2.6-1~deb9u1) …


Besides making your MIDI play on the GUI environment easy as a a point and click VLC will also be able to play MIDIs on GNU / Linux from your favourite browser (nomatter Firefox / Chrome or Opera), even though the player would play in a new PopUP Window it is easy to select once MIDI file from a random website for example – here is a directory listing of Webserver with Doom II Soundtrack in MIDI format , click over any file from list and Choose option for VLC to always remember that MIDI files has to be opened with VLC player.
 


2. Enable Firefox / IceWeasel browser to Support Website embedded MIDI files

 

 

So VLC could make you listen the downloadable MIDIs from Web pages but,
 

What if you have stumbled on an old website which was configured with very OLD HTML Code to play some nice music (or even different MIDI songs) for each part of the website (for each webpage) and you want to have the Websites created with embedded MIDIs to automatically play on Linux oncce you visit the site?


Sadly default support in Browser for MIDI across all GNU / Linux, I've used so far never worked out of the box, not that still anyone is developing modern websites with MIDIs, but still for the sake of backward compitability and for sake of interactivity it is worthy to enable embedded MIDI support in Linux

But with a couple of tunings as usual GNU / Linux can do almost everything, so here is how to enable embedded browser support for Midi on Linux (That should work with minor modifications not only on Debian / Ubuntu / ArchLinux but also on Fedoras, CentOS etc.
If you try it on any of this distributions, please drop a short comment and tell me in few lines how you made embedded midi worked on that distros.

 

apt-get install –yes timidity mozplugger

Next do restart firefox

Sometimes in order to work you might need to delete /home/[YOUR_USERNAME]/.mozilla/pluginreg.dat and restart firefox again, e.g. make a backup and give it a try:

 

cp -rpf /home/hipo/.mozilla/pluginreg.dat /home/hipo/.mozilla/pluginreg.dat.bak
rm -f /home/hipo/.mozilla/pluginreg.dat

 

Another good tip as talking for embedding MIDI support is to embed XPDF to render PDF pages inside the Browser, by default this is done by GNOME's Evince PDF reader but as it is sometimes buggy and might crash it is generally a good idea to switch to xpdf instead, if for some reason PDF is not directly displaying in browser or suddenly stopped working after some distro uipgrade, you might want to do below as well:
 

apt-get install xpdf

vim /etc/mozpluggerrc

Fin d and Comment out the line starting with:

It should look like this afterwards:

 Repeat Swallow ….
 

text/x-pdf: pdf: PDF file
#      repeat swallow(documentShell) fill: acroread -geometry +9000+9000 +useFrontEndProgram "$file"
        repeat noisy swallow(Xpdf) fill: xpdf -g +9000+9000 "$file"
        repeat noisy swallow(gv) fill: gv –safer –quiet –antialias -geometry +9000+9000 "$file"


 

3. Play Midi music in Linux text console / terminal


There is a console tool that historically has been like the Linux standard for playing midis over the years as I remember, its called timidity

 


To install timidity on .Deb based Linux:
 

linux-desktop:~$ su root
Password:
linux-desktop:~# apt-get install –yes timidity

Необходимо е да се изтеглят 0 B/580 kB архиви.
След тази операция ще бъде използвано 0 B допълнително дисково пространство.
(Reading database … 382981 files and directories currently installed.)
Preparing to unpack …/timidity_2.13.2-40.5_amd64.deb …
Unpacking timidity (2.13.2-40.5) over (2.13.2-40.5) …
Processing triggers for menu (2.1.47+b1) …
Processing triggers for man-db (2.7.6.1-2) …
Setting up timidity (2.13.2-40.5) …
Processing triggers for menu (2.1.47+b1) …

 

To test your new MIDI Synthesizer tool and make the enjoyment full you can download Doom 2 extracted MIDI Soundtrack from here
 

Once you have downloaded above Metal MIDI DOOM old school arcade soundtrack and untarred it into your home directory be it ~/doom-midis

A remark to make here is timidity is quite CPU intensive, but on modern Dual and Quad-Core PC Notebooks, the CPU load is not of a big concern.

To test and play with timidity:
 

linux-desktop~$ timidity ~/mp3/midis/*


timidity-playing-doom-midi-bunny-song-on-debian-stretch-gnome-terminal-screenshot
 

hipo@jericho:~/mp3/midis$ aplaymidi -l
 Port    Client name                      Port name
 14:0    Midi Through                     Midi Through Port-0
128:0    TiMidity                         TiMidity port 0
128:1    TiMidity                         TiMidity port 1
128:2    TiMidity                         TiMidity port 2
128:3    TiMidity                         TiMidity port 3

 


We have also the playmidi  (simple midi text console terminal player), which historically was working quite decent and I use it to in the past on my RedHat 6.0 and RedHat 7.0 to listen to my .MID format files but unfortunately as of time of writting something is wrong with it, so when I try to play MIDIs with it instead of timidity I get this erro:

 

$ playmidi *.mid
Playmidi 2.4 Copyright (C) 1994-1997 Nathan I. Laredo, AWE32 by Takashi Iwai
This is free software with ABSOLUTELY NO WARRANTY.
For details please see the file COPYING.
open /dev/sequencer: No such file or directory

Even though I tried hard to resolve that error by loading various midi related MIDI modules and following a lot of the suggestions online on how to  make /dev/sequencer work again it was all no luck.
 

Some people back in the distant year 2005, reported the problem was solved by simply loading snd-seq

But as of time of writting:

 

# modprobe snd-seq

 

Some people said in archlinux's Forum

/dev/sequencer sequencer: No such file or directory

 

is solved by loading snd-seq-oss kernel module, but on my Debian Linux 9.1 Stretch, this ain't work as well :

 

root@jericho:/home/hipo/mp3/midis# modprobe snd-seq-oss
modprobe: FATAL: Module snd-seq-oss not found in directory /lib/modules/4.9.0-3-amd64
root@jericho:/home/hipo/mp3/midis# uname -a;
Linux jericho 4.9.0-3-amd64 #1 SMP Debian 4.9.30-2+deb9u5 (2017-09-19) x86_64 GNU/Linux


Another invention of mine was to try to also link /dev/snd/seq to /dev/sequencer but this produced no positive result either:

 

# ln -sf /dev/snd/seq /dev/sequencer
# ls -al /dev/sequencer
lrwxrwxrwx 1 root root 12 окт  4 16:48 /dev/sequencer -> /dev/snd/seq


Note that after lining in that way I got following error with my attempt to play MIDIs with playmidi

# playmidi *.mid
Playmidi 2.4 Copyright (C) 1994-1997 Nathan I. Laredo, AWE32 by Takashi Iwai
This is free software with ABSOLUTELY NO WARRANTY.
For details please see the file COPYING.
there is no soundcard


Anyhow on some other Linux distributions (especially with Older Kernel versions), some of the above 3 suggested Fix might work perfectly fine so if you have some time give it a try please and drop me  a comment on how it went, you will help the GNU / Linux community out there that way.

Well never mind the bollocks, so

Now back to where I started timidity even though it will play fine it will not give any indication on the lenght of the midi song (precious information such as how much time is left until the end is over).

Hence if you prefer a player that gives you an indicator on how much is left towards the end length of each of the played MIDI file you can give a try to wildmidi:

 

linux-desktop:~$ apt-cache show wildmidi|grep -i description -A 2

Description-en: software MIDI player
 Minimal MIDI player implementation based on the wildmidi library that
 can either dump to WAV or playback over ALSA. It is intended to

Description-md5: b4b34070ae88e73e3289b751230cfc89
Homepage: http://www.mindwerks.net/projects/wildmidi/
Tag: implemented-in::c, role::program, sound::midi, sound::player,

Description: software MIDI player
Description-md5: 4673a7051f104675c73eb344bb045607
Homepage: http://wildmidi.sourceforge.net/
Bugs: https://bugs.launchpad.net/ubuntu/+filebug


If yet not installed install it after becoming admin user:

 

linux-desktop:~$ su root
Password:

linux-desktop:~# apt-get install –yes wildmidi


wildmidi is much less CPU intensive (it uses gstreamer to play (Gstreamer – open source multimedia framework)

And next give it a try by running:

 

linux-desktop:~$ wildmidi ~/mp3/midis/*

 

wildmidi-midi-lenght-status-text-console-player-for-linux-ubuntu-debian-fedora-suse

 

 

4. Editting MIDI files with Free Software and Proprietary MIDI Editor Programs

 


If you want a professional software that can play Midi in a fuzzy interactive GUI way and have some extra possibilities to edit MIDIs and other format give a try to Muse Sequencer:
 

 

linux-desktop:~$ sudo apt-get install –yes muse

The following NEW packages will be installed:
  muse
0 upgraded, 1 newly installed, 0 to remove and 38 not upgraded.
Need to get 5814 kB of archives.
After this operation, 21.0 MB of additional disk space will be used.
Get:1 http://deb.debian.org/debian stretch/main amd64 muse amd64 2.1.2-3+b1 [5814 kB]
Fetched 5814 kB in 2s (2205 kB/s)                             
    are supported and installed on your system.
Preconfiguring packages …
Selecting previously unselected package muse.
(Reading database … 382981 files and directories currently installed.)
Preparing to unpack …/muse_2.1.2-3+b1_amd64.deb …
Unpacking muse (2.1.2-3+b1) …
Processing triggers for mime-support (3.60) …
Processing triggers for desktop-file-utils (0.23-1) …
Processing triggers for doc-base (0.10.7) …
Processing 1 added doc-base file…
Registering documents with scrollkeeper…
Processing triggers for man-db (2.7.6.1-2) …
Processing triggers for shared-mime-info (1.8-1) …
Unknown media type in type 'all/all'
Unknown media type in type 'all/allfiles'
Processing triggers for gnome-menus (3.13.3-9) …
Setting up muse (2.1.2-3+b1) …
Processing triggers for hicolor-icon-theme (0.15-1) …


 

Below is short description what Muse can do for you:

 

MusE is a MIDI/audio sequencer with recording and editing capabilities.
 Some Highlights:
 

  * Standard midifile (smf) import-/export.
  * Organizes songs in tracks and parts which you can arrange with
    the part editor.
  * MIDI editors: pianoroll, drum, list, controller.
  * Score editor with high quality postscript printer output.
  * Realtime: editing while playing.
  * Unlimited number of open editors.
  * Unlimited undo/redo.
  * Realtime and step-recording.
  * Multiple MIDI devices.
  * Unlimited number of tracks.
  * Sync to external devices: MTC/MMC, Midi Clock, Master/Slave.
  * Audio tracks, LADSPA host for master effects.
  * Multithreaded.
  * Uses raw MIDI devices.
  * XML project file.
  * Project file contains complete app state (session data).
  * Application spanning Cut/Paste Drag/Drop.

 

linux-desktop~:$ muse

muse-advanced-midi-editor-free-software-for-linux

 

Below is another non-free program that you might, try if MusE doesn't fit your needs (is not rich enough for editting capabilities is bitwig (though I don't recommend since it is not free software)

bitwig – Bitwig Studio is a multi-platform music-creation system for production, performance and DJing, with a focus on flexible editing tools and a super-fast workflow.
 


bitwig-midi-and-audio-non-free-software-advanced-useful-sound-editor-for-linx


 

5. Some examples for Text editing and MIDI Conversion to CSV and ABC file formats There is pretty much more

For the MIDI Extremists who or people that create MIDIs and want to learn how a MIDI is made (the content of it etc.), I suggest you take a look at these 3 command line MIDI editing / conversion tools
 

  • midi2abc – A little tool to create MIDI formats to ABC format
  • midi2csv – Conver tour Favourite MIDI files to CSV for educational purposes so see what Channels, Tracks and Time Intervals is a MIDI song mad
  • midicopy – Copy selected, track, channel, time interval of MIDI file to another MIDI file3

 

Well, that's all folks now enjoy your MIDIs and don't forget to donate, as I'm jobless at the moment and the only profit I make is just a few bucks out of advertisement on this blog.
 

Disable Bluetooth on CentOS / RHEL (Redhat) / Fedora Linux servers – Disable hidd bluetooth devices

Thursday, January 29th, 2015

Disable_Bluetooth_on_CentOS_RHEL_Redhat_Fedora_Linux_servers_-_Disable_hidd_bluetooth_devices-logo

Bluetooth protocol on Linux is nice to have (supported) on Linux Desktop systems to allow easy communication wth PDAs, Tablets, Mobiles, Digital Cameras etc, However many newly purchased dedicated servers comes with Bluetooth support enabled which is a service rarely used, thus it is a good strong server security / sysadmin practice to remove the service supporting Blueetooth (Input Devices) on Linux hosts this is the hidd (daemon) service, besides that there are few Linux kernel modules to enable bluetooth support and removing it is also a very recommended practice while configuring new Production servers. 

Leaving Blueetooth enabled on Linux just takes up memory space and  potentially is a exposing server to possible security risk (might be hacked) remotely. 
Thus eearlier I've blogged on how bluetooth is disabled on Debian / Ubuntu Linux servers an optimization tuning (check) I do on every new server I have to configure, since administrating both RPM and Deb Linux distributions I usually also remove bluetooth hidd service support on every CentOS / RHEL / Fedora Linux – redhat  (where it is installed), here is how :

 

1. Disable Bluetooth in CentOS / RHEL Linux


a) First check whether hidd service is running on server:
 

[root@centos ~]# ps aux |grep -i hid
… 


b) Disable bluetooth services
 

[root@centos ~]# /etc/init.d/hidd stop
[root@centos ~]# chkconfig hidd off
[root@centos ~]# chkconfig bluetooth off
[root@centos ~]# /etc/init.d/bluetooth off


c) Disable any left Bluetooth kernel module (drivers), not to load on next server boot
 

[root@centos ~]# echo 'alias net-pf-31 off' >> /etc/modprobe.conf


If you don't need or intend to use in future server USBs it is also a good idea to disable USBs as well:
 

[root@centos ~]# lsmod|grep -i hid
usbhid                 33292  0
hid                    63257  1 usbhid
usbcore               123122  4 usb_storage,usbhid,ehci_hcd


[root@centos ~]# echo 'usbhid' >> /etc/modprobe.d/blacklist.conf
[root@centos ~]# echo 'hid' >> /etc/modprobe.d/blacklist.conf
[root@centos ~]# echo 'usbcore' >> /etc/modprobe.d/blacklist.conf

 

2. Disable Bluetooth on Fedora Linux

Execute following:
 

[hipo@fedora ~]# /usr/bin/sudo systemctl stop bluetooth.service
[hipo@fedora ~]# /usr/bin/sudo systemctl disable bluetooth.service

 
3. Disable Bluetooth on Gentoo / Slackware and other Linuces

An alternative way to disable bluetooth that should work across all Linux distributions / versions is:
 

[root@fedora ~]# su -c 'yum install rfkill'
[root@fedora ~]# su -c 'vi /etc/rc.d/rc.local'


Place inside, something like (be careful not to overwrite something, already execution on boot):
 

#!/bin/sh
rfkill block bluetooth
exit 0


4. Disable any other unnecessery loaded service on boot time

It is a good idea to also a good idea to check out your server running daemons, as thoroughfully as possible and remove any other daemons / kernel modules not being used by server.

To disable all unrequired services, It is useful to get a list of all enabled services, on RedHat based server issue:

 

[root@cento ~]#  chkconfig –list |grep "3:on" |awk '{print $1}'


 A common list of services you might want to disable if you're configuring (Linux, Apache, MySQL, PHP = LAMP) like server is:
 

chkconfig anacron off
chkconfig apmd off
chkconfig atd off
chkconfig autofs off
chkconfig cpuspeed off
chkconfig cups off
chkconfig cups-config-daemon off
chkconfig gpm off
chkconfig isdn off
chkconfig netfs off
chkconfig nfslock off
chkconfig openibd off
chkconfig pcmcia off
chkconfig portmap off
chkconfig rawdevices off
chkconfig readahead_early off
chkconfig rpcgssd off
chkconfig rpcidmapd off
chkconfig smartd off
chkconfig xfs off
chkconfig ip6tables off
chkconfig avahi-daemon off
chkconfig firstboot off
chkconfig yum-updatesd off
chkconfig mcstrans off
chkconfig pcscd off
chkconfig bluetooth off
chkconfig hidd off


In most cases you can just run script like this – centos-disable_non-required_essential_services_for_lamp_server.sh.
 

Another useful check the amount of services each of the running server daemons is using, here is how:
 

ps aux | awk '{print $4"t"$11}' | sort | uniq -c | awk '{print $2" "$1" "$3}' | sort -nr


Output of memory consumption check command is here

How to remove and disable BlueTooth support on Debian GNU / Linux servers

Thursday, October 18th, 2012

How to remove / disable bluetooth support on Debian GNU / Linux servers
If you running Debian Squeeze Linux (as server Apache, MySQL, Qmail etc.) on brand new purchased hardware with bluetooth support; you will notice default Linux kernel will detect and load modules for Bluetooth

This would not be a problem only if Bluetooth does not pose possible errors or (even at cases even maybe system hangs ups?). The actual reason in my case to want to disable bluetooth on a productive Linux server operating like host was I found out in dmesg produced output, some errors related to Bluetooth, here they are:


root@deb:~# dmesg|grep -i 'call trace' -A 8
[323406.744439] Call Trace:
[323406.744440] [] ? lapic_next_event+0x18/0x1d
[323406.744450] [] ? __report_bad_irq+0x30/0x7d
[323406.744453] [] ? note_interrupt+0x105/0x16e
[323406.744455] [] ? handle_fasteoi_irq+0x93/0xb5
[323406.744458] [] ? handle_irq+0x17/0x1d
[323406.744460] [] ? do_IRQ+0x57/0xb6
[323406.744463] [] ? ret_from_intr+0x0/0x11
[323406.744464]

I saw this error and similar ones occuring, every now and then obviously displaying something wents wrongs with IRQs related to BlueTooth Communication with Kernel (as it keeps processing requests loaded in system memory) …

Well anyways having the bluetooth kernel module loaded on memory just takes up few chunks of useless assigned memory.
I don't have intention to use bluetoothever in future on these host so I decided to completely remove bluetooth support on those Debian.

1. Remove blueetoh support on Debian GNU / Linux

First to check info about the loaded kernel module bluetooth.ko and its assigned module load alias run:


root@deb:~# /sbin/modinfo bluetooth
filename: /lib/modules/2.6.32-5-amd64/kernel/net/bluetooth/bluetooth.ko
alias: net-pf-31
license: GPL
version: 2.15
description: Bluetooth Core ver 2.15
author: Marcel Holtmann
srcversion: 9FD5BF98FC88505DC637909
depends: rfkill
vermagic: 2.6.32-5-amd64 SMP mod_unload modversions

Secondly disable memory preloaded bluetooth.ko on the current host with cmds:


root@deb:~# rmmod -f bnep
root@deb:~# rmmod -f l2cap
root@deb:~# rmmod -f sco
root@deb:~# rmmod -f bluetooth

Default way to control if Bluetooth (on host support is ON or OFF) is through /etc/default/bluetooth. Inside /etc/default/bluetooth is a control variable:


BLUETOOTH_ENABLED=1

To shut it off change its value to 0:


BLUETOOTH_ENABLED=0

Then to permanently prevent bluetooth.ko from being ever in future loaded its also good idea to blacklist modules – bnep, btusb, bluetooth:


root@deb:~# echo 'blacklist bnep' >> /etc/modprobe.d/bluetooth.conf
root@deb:~# echo 'blacklist btusb' >> /etc/modprobe.d/bluetooth.conf
root@deb:~# echo 'blacklist bluetooth' >> /etc/modprobe.d/bluetooth.conf

Onwards re-build, current kernel initramfs:


root@deb:~# update-initramfs -u -k `uname -r` -v
......
......

Next update boot init scripts with update-rc.d to make sure bluetooth (service / daemon) is not started:


root@deb:~# update-rc.d bluetooth remove
......

That's all bluetooth will not load up anymore on next boot and at present time will not take up useless mem space.

2. Re-enable disabled blueetooth on Debian Linux
 
I've been asked in one of comments, what to do If you need to re-enable bluetooth on your Debian Linux at some time in future, so here are the steps to turn back blueetooth on again


/etc/modprobe.d/bluetooth.conf

Change variable:

BLUETOOTH_ENABLED=0

to 

BLUETOOTH_ENABLED=1

Open  /etc/modprobe.d/bluetooth.conf and remove any blacklisted modules, e.g:

'blacklist bnep'
'blacklist btusb'
&39;blacklist bluetooth'

Rebuild again kernel ramfs

root@deb:~# update-initramfs -u -k `uname -r` -v
 
Enjoy 🙂

How to disable IPv6 on Debian / Ubuntu / CentOS and RHEL Linux

Friday, December 9th, 2011

I have few servers, which have automatically enabled IPv6 protocols (IPv6 gets automatically enabled on Debian), as well as on most latest Linux distribituions nowdays.

Disabling IPv6 network protocol on Linux if not used has 2 reasons:

1. Security (It’s well known security practice to disable anything not used on a server)
Besides that IPv6 has been known for few criticil security vulnerabilities, which has historically affected the Linux kernel.
2. Performance (Sometimes disabling IPv6 could have positive impact on IPv4 especially on heavy traffic network servers).
I’ve red people claiming disabling IPv6 improves the DNS performance, however since this is not rumors and did not check it personally I cannot positively confirm this.

Disabling IPv6 on all GNU / Linuces can be achieved by changing the kernel sysctl settings net.ipv6.conf.all.disable_ipv6 by default net.ipv6.conf.all.disable_ipv6 equals 1 which means IPv6 is enabled, hence to disable IPv6 I issued:

server:~# sysctl net.ipv6.conf.all.disable_ipv6=0

To set it permanently on system boot I put the setting also in /etc/sysctl.conf :

server:~# echo 'net.ipv6.conf.all.disable = 1 >> /etc/sysctl.conf

The aforedescribed methods should be working on most Linux kernels version > 2.6.27 in that number it should work 100% on recent versions of Fedora, CentOS, Debian and Ubuntu.

To disable IPv6 protocol on Debian Lenny its necessery to blackist the ipv6 module in /etc/modprobe.d/blacklist by issuing:

echo 'blacklist ipv6' >> /etc/modprobe.d/blacklist

On Fedora / CentOS there is a another universal “Redhat” way disable IPv6.

On them disabling IPv6 is done by editting /etc/sysconfig/network and adding:

NETWORKING_IPV6=no
IPV6INIT=no

I would be happy to hear how people achieved disabling the IPv6, since on earlier and (various by distro) Linuxes the way to disable the IPv6 is probably different.
 

Alto to stop Iptables IPV6 on CentOS / Fedora and RHEL issue:

# service ip6tables stop

# service ip6tables off

How to make GRE tunnel iptables port redirect on Linux

Saturday, August 20th, 2011

I’ve recently had to build a Linux server with some other servers behind the router with NAT.
One of the hosts behind the Linux router was running a Window GRE encrypted tunnel service. Which had to be accessed with the Internet ip address of the server.
In order < б>to make the GRE tunnel accessible, a bit more than just adding a normal POSTROUTING DNAT rule and iptables FORWARD is necessery.

As far as I’ve read online, there is quite of a confusion on the topic of how to properly configure the GRE tunnel accessibility on Linux , thus in this very quick tiny tutorial I’ll explain how I did it.

1. Load the ip_nat_pptp and ip_conntrack_pptp kernel module

linux-router:~# modprobe ip_nat_pptp
linux-router:~# modprobe ip_conntrack_pptp

These two modules are an absolutely necessery to be loaded before the remote GRE tunnel is able to be properly accessed, I’ve seen many people complaining online that they can’t make the GRE tunnel to work and I suppose in many of the cases the reason not to be succeed is omitting to load this two kernel modules.

2. Make the ip_nat_pptp and ip_nat_pptp modules to load on system boot time

linux-router:~# echo 'ip_nat_pptp' >> /etc/modules
linux-router:~# echo 'ip_conntrack_pptp' >> /etc/modules

3. Insert necessery iptables PREROUTING rules to make the GRE tunnel traffic flow

linux-router:~# /sbin/iptables -A PREROUTING -d 111.222.223.224/32 -p tcp -m tcp --dport 1723 -j DNAT --to-destination 192.168.1.3:1723
linux-router:~# /sbin/iptables -A PREROUTING -p gre -j DNAT --to-destination 192.168.1.3

In the above example rules its necessery to substitute the 111.222.223.224 ip address withe the external internet (real IP) address of the router.

Also the IP address of 192.168.1.3 is the internal IP address of the host where the GRE host tunnel is located.

Next it’s necessery to;

4. Add iptables rule to forward tcp/ip traffic to the GRE tunnel

linux-router:~# /sbin/iptables -A FORWARD -p gre -j ACCEPT

Finally it’s necessery to make the above iptable rules to be permanent by saving the current firewall with iptables-save or add them inside the script which loads the iptables firewall host rules.
Another possible way is to add them from /etc/rc.local , though this kind of way is not recommended as rules would add only after succesful bootup after all the rest of init scripts and stuff in /etc/rc.local is loaded without errors.

Afterwards access to the GRE tunnel to the local IP 192.168.1.3 using the port 1723 and host IP 111.222.223.224 is possible.
Hope this is helpful. Cheers 😉

Fix FTP client error 425 Unable to build data connection: No route to host (Cause and Solution)

Monday, July 8th, 2013

ftp fix client 425 unable to-build data connection no route to host Linux
I just configured new dedicated server. One of requirement was dedicated server to support connections via FTP transfer protocol and few users to have access via it.
I added users with required permissions to directory structure and went on to test it with Linux ftp command, i.e.:
 

 

hipo@pcfreak:~$ ftp remote-host-name

Connected to remote-host-name.com
220 ProFTPD 1.3.3a Server (Matusala) [xx.xxx.xxx.xxx.xx]
Name (Matusala:hipo): testing-user
331 Password required for testing-user
Password:
230 User testing-user logged in

Remote system type is UNIX.
Using binary mode to transfer files.

 

ftp> ls

 

200 PORT command successful
425 Unable to build data connection: No route to host

ftp> exit

 

221 Goodbye.

 

As you see from above FTP paste even simple commands like "ls" failed to work with error:

425 Unable to build data connection: No route to host

I thought somehow I have configured on server some paranoid firewall, so tested same connection with iptables rules flushed, e.g.: matusala:~# iptables -F
matusala:~# iptables -t nat -F

Even after flushing firewall message persisted, so I googled around to see the what causes the error. The same error was hit by many users, and as I read, understand what causes is FTP server host is located behind some DMZ or firewall (as it was not my firewall I suppose, the dedicated provider has some firewall rules which are blocking FTP traffic on standard FTP TCP / UDP ports, port 20 and 21 ).
Fix is to enable in Linux kernel ip_nat_ftp or in newer Linux kernels module nf_nat_ftp:

matusala:~# modprobe ip_nat_ftp
matusala:~# modprobe nf_nat_ftp

or
To make ip_nat_ftp load permanently on Debian and Ubuntu servers:

matusala:~# echo 'ip_nat_ftp' >> /etc/modules
matusala:~# echo 'nf_nat_ftp' >> /etc/modules

One important note to make here is if you're testing the connection between two Linux servers it is possible the server from which you're running the client to have missing nf_nat_ftp loaded, so if error persist and you're testing remote FTP server from local ftp client on linux load same modules on localhost and you're done 🙂

How to disable PC Spaker on Debian and Ubuntu Linux

Sunday, May 13th, 2012

 

How to disable pc-speaker on Linux / PC-Speaker Old Desktop Computer picture

A PC Speaker is helpful as it could be used as a tool for diagnosing system hardware failures (different systems produce different beep sequences depending on the machine BIOS type).
Using the instructions for the respective BIOS vendor and version one could determine the type of problem experienced by a machine based on the sequence and frequency of sounds produced by the SPEAKER.
Lets say a hardware component on a server is down with no need for a monitor or screen to be attached you can say precisely if it is the hard drive, memory or fan malfunctioning…

Generally speaking historically embedded PC Speaker was inseparatable part of the Personal Computers, preceding the soundblasters, now this is changing but for compitability sake many comp equipment vendors still produce machines with pc-speaker in.
Some newer machines (mostly laptops) are factory produced with no PC-SPEAKER component anymore.
For those who don't know what is PC SPEAKER, it is a hardware device capable of emitting very simple short beep sounds at certain system occasions.

Talking about PC-Speaker, it reminds me of the old computer days, where we used pc-speakers to play music in DOS quite frequently.
It was wide practice across my friends and myself to use the pc-speaker to play Axel Folly and other mod files because we couldn't afford to pay 150$ for a sound cards. Playing a song over pc-speaker is quite a nice thing and it will be a nice thing if someone writes a program to be able to play songs on Linux via the pc-speaker for the sake of experiment.

As of time of writting, I don't know of any application capable of playing music files via the pc-speaker if one knows of something like this please, drop me a comment..

As long as it is used for hardware failure diagnosis the speaker is useful, however there are too many occasions where its just creating useless annoying sounds.
For instance whether one uses a GUI terminal or console typing commands and hits multiple times backspace to delete a mistyped command. The result is just irritating beeps, which could be quite disturbing for other people in the room (for example if you use Linux as Desktop in heterogeneous OS office).
When this "unplanned" glitchering beeps are experienced 100+ times a day you really want to break the computer, as well as your collegues are starting to get mad (if not using their headphones) 🙂

Hence you need sometimes to turn off the pc-speaker to save some nerves.

Here is how this is done on major Linux distros.

On Debian and most other distros, the PC SPEAKER is controlled by a kernel module, so to disable communication with the speaker you have to remove the kernel module.

On Debian and Fedora disabling pcspeaker is done with:

# modprobe -r pcspkr

Then to permanently disable load of the pcspkr module on system boot:

debian:~# echo 'blacklist pcspkr' >> /etc/modprobe.d/blacklist.conf

On Ubuntu to disable load on boot /etc/modprobe.d/blacklist, file should be used:

ubuntu:~# echo 'blacklist pcspkr' >> /etc/modprobe.d/blacklist
Well that's all folks …

How to fix Thinkpad R61i trackpoint (mouse pointer) hang ups in GNU / Linux

Wednesday, February 1st, 2012

Earlier I've blogged on How to Work Around periodically occuring TrackPoint Thinkpad R61 issues on GNU / Linux . Actually I thought the fix I suggested there is working but I was wrong as the problems with the trackpoint reappeared at twice or thrice a day.

My suggested fix was the use of one script that does periodically change the trackpoint speed and sensitivity to certain numbers.

The fix script to the trackpoint hanging issue is here

Originally I wrote the script has to be set to execute through crontab on a periods like:

0,30 * * * * /usr/sbin/restart_trackpoint.sh >/dev/null 2>&1

Actually the correct values for the crontab if you use my restart_trackpoint.sh script are:

0,5,10,15,20,25,30,35,40,45,50,55,58 * * * * /usr/sbin/restart_trackpoint.sh >/dev/null 2>&3

ig it has to be set the script is issued every 5 minutes to minimize the possibility for the Thinkpad trackpoint hang up issue.

One other thing that helps if trackpoint stucks is setting in /etc/rc.local is psmouse module to load with resetafter= parameter:

echo '/sbin/rmmod psmouse; /sbin/modprobe psmouse resetafter=30' >> /etc/rc.local

 

Solve ALSA audio and mic issues on Lenovo Thinkpads on Debian and Ubuntu Linux

Wednesday, January 11th, 2012

Since I've blogged about my recent skype issues. I've played a lot with pulseaudio, alsa, alsa-oss to experimented a lot until I figured out why Skype was failing to properly delivery sound and record via my embedded laptop mic.

Anyways, while researching on the cause of my Thinkpad r61 mic issues, I've red a bunch of blog posts by people experiencing microphone oddities with Lenovo Thinkpads

Throughout the search I come across one very good article, which explained that in many cases the Thinkpad sound problems are caused by the snd-hda-intel alsa kernel module. snd-hda-intel fails to automatically set proper sb model type argument during Linux install when the soundcard is initialized with some argument like options snd-hda-intel model=auto

Hence, the suggested fix which should resolve this on many Thinkpad notebooks is up to passing the right module argument:

To fix its neceessery to edit /etc/modprobe.d/alsa-base.conf .

debian:~# vim /etc/modprobe.d/alsa-base.conf

Find the line in the file starting with:
options snd-hda-intel model=

and substitute with:

options snd-hda-intel model=thinkpad

Finally a restart of Advaned Linux Sound Architecture (alsa) is required:

debian:~# /etc/init.d/alsa restart
...

At most cases just restarting the alsa via its init script is not enough, since the ssnd-hda-intel kernel module is already in use by some program or something, so its best to do a reboot to make sure the module is loaded with the new model=thinkpad argument.

My exact laptop sound card model is:

debian:~# lspci |grep -i audio
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 03)

After changing the module and using alsamixer and aumix to make sure mic is unmuted and its volume is high enough, mic sound rec works fine.

Upgrading Skype 2.0 to Skype 2.2 beta on Debian GNU / Linux – Skype Mic hell

Saturday, December 31st, 2011

Making Skype work with Alsa on Debian GNU / Linux

Though, I'm GNU / Linux user for many years now. I have to say, everything is not so perfect as many people present it.
Configuring even simple things related to multimedia on Linux is often a complete nightmare.
An example, today I've decided to upgrade my 32 bit Skype version 2.0 beta for Linux to 64 bit Skype 2.2 beta .
The reason I was motivated to upgrade skype was basicly 2.

a) My Skype run through 32 bit binary emulation with /usr/bin/linux32

b) I had issues with my skype if someone give me a Skype Call, while I have a flash video or some other stream in Browser (let's say Youtube).
Actually being unable to receive a skype call or initiate one while I have some kind of music running in the background or just some kind of Youtube video paused was really annoying. Hence until now, everytime I wanted to speak over skype I had to close all Browser windows or tabs that are using my sound card and then restart my Skype program ….

Just imagine how ridiculous is that especially for a modern Multimedia supporting OS as Linux is. Of course the problems, I've experienced wasn't directly a problem of Linux. The problems are caused by the fact I have to use the not well working proprietary software version of Skype on my Debian GNU / Linux.
I would love to actually boycott Skype as RMS recommends, but unfortunately until now I can't, since many of my friends as well as employers use Skype to connect with me on daily basis.
So in a way I had to migrate to newer version of skype in order to make my Linux experience a bit more desktop like …

Back to the my skype 2.0 to 2.2. beta upgrade story, the overall Skype upgrade procedure was easy and went smootlhy, setting correct capturing later on however was a crazy task ….
Here is the step by step to follow to make my upgraded skype and internal notebook mic play nice together:

1. Download 64 bit Skype for Debian from skype.com

For the sake of preservation in case it disappears in future, I've made a mirror of skype for debian you can download here
My upgrade example below uses directly the 64 bit Skype 2.2beta binary mirror:

Here are the cmds once can issue if he has to upgrade to 2.2beta straight using my mirrored skype:

debian:~# wget https://www.pc-freak.net/files/skype-debian_2.2.0.35-1_amd64.deb
...

2. Remove the old version of skype

In my case I have made my previous skype installation using .tar.bz2 archive and not a debian package, however for some testing I also had a version of skype 2.0beta installed as a deb so for the sake of clarity I removed the existing skype deb install:

debian:~# dpkg -r skype
...

3. Install skype-debian_2.2.0.35-1_amd64.deb downloaded deb

debian:~# dpkg -i skype-debian_2.2.0.35-1_amd64.deb
...

After installing skype, I installed pavucontrol A volume control for the PulseAudio sound server

4. Install pavucontrol

debian:~# apt-get install pavucontrol

PavUcontrol PulseAudio mixer screenshot

Pavucontrol has plenty of sound configurations and enables the user to change many additional settings which cannot be tuned in alsamixer

pavucontrol was necessery to play with until I managed to make my microphone able to record.

5. Build and install latest Debian (Testing) distribution alsa driver

debian:~# aptitude install module-assistant
debian:~# m-a prepare
debian:~# aptitude -t testing install alsa-source
debian:~# m-a build alsa
debian:~# m-a install alsa
debian:~# rmmod snd_hda_intel snd_pcm snd_timer snd soundcore snd_page_alloc
debian:~# modprobe snd_hda_intel
debian:~# echo 'options snd-hda-intel model=auto' >> /etc/modprobe.d/alsa-base.conf

In my case removing the sound drivers and loading them once again did not worked, so I had to reboot my system before the new compiled alsa sound modules gets loaded …
The last line echo 'options snd-hda-intel model=auto' … was necessery for my Thinkpard r61 Intel audio to work out. For some clarity my exact sb model is:

debian:~$ lspci |grep -i audio
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 03)

For other notebooks with different sound drivers echo 'options snd-hda-intel model=auto' … should be omitted.

6. Tune microphone and sound settings in alsamixer

debian:~$ alsamixer

Alsamixer Select Soundcard Debian Linux Screenshot
Right after launching alsamixer I had to press F6: Select Sound Card and choose my sound card (0 HDA Intel).

Following my choice I unmuted all the microphones and enabled Microphone Boost as well as did some adjustments to the MIC volume level.

Alsamixer My Intel SoundCard Debian Linux

Setting proper MIC Volume levels is absolutely necessery, otherwise there is a constant noise getting out of the speakers …

7. Use aumix to set some other sound settings

For some unclear reasons, besides alsamixer , I often had to fix stuff in aumix . Honestly I don't understand where exactly aumix fits in the picture with Alsa and my loaded alsa sound blaster module?? If someone can explain I'll be thankful.

Launch aumix to further adjust some sound settings …

debian:~$ aumix

Aumix Debian GNU Linux Squeeze Screenshot

In above screenshot you see, my current aumix settings which works okay with mic and audio output.

9. Test Microphone the mic is capturing sounds correctly

Set ~/.asoundrc configuration for Skype

Edit ~/.asoundrc and put in:

pcm.pulse {
type pulse
}
ctl.pulse {
type pulse
}
pcm.!default {
type pulse
}
ctl.!default {
type pulse
}
pcm.card0 {
type hw
card 0
}
ctl.card0 {
type hw
card 0
}
pcm.dsp0 { type plug slave.pcm "hw:0,0" }
pcm.dmixout {
# Just pass this on to the system dmix
type plug
slave {
pcm "dmix"
}
}
pcm.skype {
type asym
playback.pcm "skypeout"
capture.pcm "skypein"
}
pcm.skypein {
# Convert from 8-bit unsigned mono (default format set by aoss when
# /dev/dsp is opened) to 16-bit signed stereo (expected by dsnoop)
#
# We cannot just use a "plug" plugin because although the open will
# succeed, the buffer sizes will be wrong and we will hear no sound at
# all.
type route
slave {
pcm "skypedsnoop"
format S16_LE
}
ttable {
0 {0 0.5}
1 {0 0.5}
}
}
pcm.skypeout {
# Just pass this on to the system dmix
type plug
slave {
pcm "dmix"
}
}
pcm.skypedsnoop {
type dsnoop
ipc_key 1133
slave {
# "Magic" buffer values to get skype audio to work
# If these are not set, opening /dev/dsp succeeds but no sound
# will be heard. According to the ALSA developers this is due
# to skype abusing the OSS API.
pcm "hw:0,0"
period_size 256
periods 16
buffer_size 16384
}
bindings {
0 0
}
}
I'm not 100% percent if putting those .asoundrc configurations are necessery. I've seen them on archlinux's wiki as a perscribed fix to multiple issues with Skype sound in / out.

Onwardds, for the sake of test if my sound settings set in pavucontrol enables the internal mic to capture sound I used two programs:

1. gnome-sound-recorder
2. arecord

gnome-sound-recorder GNU / Linux Screenshot
gnome-sound-recorder

gnome-sound-recorder is probably used by most GNOME users, though I'm sure Linux noviced did not play with it yet.

arecord is just a simple console based app to capture sound from the microphone. To test if the microphone works I captured a chunk of sounds with cmd:

debian:~$ arecord cow.wav
Recording WAVE 'cow.wav' : Unsigned 8 bit, Rate 8000 Hz, Mono

Later on I played the file with aplay (part of alsa-utils package in Debian), to check if I'll hear if mic succesfully captured my voice, e.g.:

debian:~$ play cow.wav
cow.wav:
File Size: 22.0k Bit Rate: 64.1k
Encoding: Unsigned PCM
Channels: 1 @ 8-bit
Samplerate: 8000Hz
Replaygain: off
Duration: 00:00:02.75
In:100% 00:00:02.75 [00:00:00.00] Out:22.0k [-=====|=====-] Clip:0
Done.

By the way, the aplay ASCII text equailizer is really awesome 😉 aplay is also capable of playing (Ogg Vorbis .ogg) free sound format.

Further on, I launched the new installed version of skype and tested Skype Calls (Mic capturing), with Skype Echo / Sound Test Service
I'll be glad to hear if this small article, helped anybody to fix any skype Linux related issues ?. I would be happy to hear also from people who had similar issues with a different fixes for skype on Linux.
Its also interesting to hear from Ubuntu and other distributions users if following this tutorial had somehow helped in resolving issues with Skype mic.