Posts Tagged ‘kernel’
Thursday, July 14th, 2011 
Just recently it was necessery to load up a tun kernel module on few CentOS Linux servers.
I’m using Debian on daily basis, and everybody that had even little of experience with Debian should already be aware about the existence of the handy:
/etc/modules file.
On Debian to enable a certain kernel module to load up on Linux boot, all necessery is to just place the kernel module name in /etc/modules.
For example loading the tun tunneling kernel module I issue the command:
debian:~# echo tun >> /etc/modules
I wondered if CentOS, also supports /etc/modules as it was necessery now to add this tun module to load up on CentOS’s boot.
After a bit of research I’ve figured out CentOS does not have support for adding modules names in /etc/modules , anyhow after consulting CentOS documentation on http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-kernel-modules-persistant.html , I found CentOS and RHEL use /etc/rc.modules instead of Debian’s /etc/modules to load up any custom kernel modules not loaded by default during system boot.
Therefore instructing the RHEL Linux to load up my desired tun module in kernel on next boot was as easy as executing:
[root@centos ~]# echo 'modprobe tun' >> /etc/rc.modules
[root@centos ~]# chmod +x /etc/rc.modules
Now on next boot CentOS will load up the tun module in kernel. Achiving the same module load up is also possible through /etc/rc.local , but it’s not recommended way as /etc/rc.local would load up the kernel module after all of the rest init boot scripts complete and therefore will load up the module slightly later, at the final boot stage.
Tags: basis, boot, boot scripts, boot stage, CentOS, command, custom, custom kernel, daily basis, Debian, deployment guide, everybody, existence, experience, final boot, kernel, kernel module, kernel modules, Linux, linux servers, modprobe, Module, modulesNow, name, necessery, rhel, root, stage, support, system boot, use, way
Posted in Linux, System Administration | No Comments »
Monday, April 11th, 2011 
If you’re experiencing problems with maximising flash (let’s say youtube) videos on your Debian or Ubuntu or any other debian derivative.
You’re not the only one! I myself has often experienced the same annoying issue.
The flash fullscreen failures or slownesses are caused by flash player’s attempts to use directly your machine hardware, as Linux kernel is rather different than Windows and the guys from Macromedia are creating always a way more buggy port of flash for unix than it’s windows versions, it’s quite normal that the flash player is unable to properly address the computer hardware on Linux.
As i’m not programmer and I couldn’t exactly explain the cause for the fullscreen flash player mishaps, I’ll skip this and right give you the two command lines solution:
debian:~# mkdir /etc/adobe
debian:~# echo "OverrideGPUValidation = 1" >> /etc/adobe/mms.cfg
This should fix it for, you now just restart your Icedove (Firefox), Epiphany Opera or whatever browser you’re used to and launch some random video in youtube to test the solution, hopefully it should be okay 😉 But you never know with flash let’s just hope that very soon the open flash alternative gnash will be production ready and at last we the free software users will be freed from the evil “slavery” of adobe’s non-free flash player!
Though this tip is tested on Debian based Linux distributions it should most likely work same in all kind of other Linuxes.
The tip should also probably have effect in FreeBSD, though the location of the adobe directory and mms.cfg should probably be /usr/local/etc/adobe, I’ll be glad to hear from some FreeBSD user if including the OverrideGPUValidation = 1 flash option to mms.cfg like below:
# mkdir /usr/local/etc/adobe
# echo "OverrideGPUValidation = 1" >> /usr/local/etc/adobe/mms.cfg
would have an impact on any flash player fullscreen issues on FreeBSD and other BSD direvative OSes that run the linux-flash port.
Tags: Adobe, adobe flash, adobedebian, browser, BSD, buggy, cause, cfg, command, Computer, computer hardware, derivative, Flash, flash fullscreen, flash issues, flash option, free flash player, free software users, freebsd user, fullscreen flash, gnash, hardware, Icedove, impact, issue, kernel, linux distributions, linux flash, linuxes, location, machine hardware, macromedia, mms, option, oses, player, port, production, programmer, Resolving, right, slavery, software, solution, sudo, tip, Ubuntu, video, way, windows versions, work, youtube, youtube videos
Posted in Linux, Linux and FreeBSD Desktop, Linux Audio & Video | No Comments »
Monday, April 11th, 2011 A friend of mine has recommended, few websites which are quite useful in checking what kind of information a remote website could possibly retrieve about your system. I’ve found quite useful as they expose the high level of browser security there is nowdays even on a Linux based systems.
I’ve been stunned that so many information about my Linux desktop could be mined even when I use my browser through a tor network.
Here are the websites you might also like to check and possibly afterwards improve your Browser security:
http://anon.inf.tu-dresden.de/help/jap_help/en/help/security_test.html
http://www.proxy-list.org/en/show-my-ip.php
http://leader.ru/secure/who.html
I was rather shocked that some information that could be retrieved on my Linux host could even reveal fundamental details about my Linux Desktop like a version of my currently running Linux kernel!
In the past I’ve blogged an article which is quite related to the topic of Internet Anonimity and Browser security
You might consider checking my old article How to improve your web browser security and better secure your personal identity privacy on the internet here
I will take some steps further to look on how to further decrease the amount of OS sensitive data revealed by my browser and will further blog when I find ways for better ways to anonimize my surging.
Tags: amount, anonimity, anonimize, blog, browser, checking, Desktop, dresden, host, identity, information, ip, kernel, kind, level, Linux, linux desktop, linux host, mine, network, personal identity, Privacy, privacy on the internet, proxy list, ru, security, security test, sensitive data, topic, tor, version, web, web browser security, website
Posted in Computer Security, Linux, Linux and FreeBSD Desktop | 2 Comments »
Tuesday, February 12th, 2008 A new exploit is out vmsplice Local root exploit. All Linux users are advised to update. Debian has released a new package fixing the issue. http://www.securityfocus.com/archive/1/487876A friends of mine static informed me that the exploit Doesn’t rewt an updated CentOS. My debian system has proved vulnerable. I was pretty much surprisedwhen a friend of mine called and said hey man try logging with your user “hipo” :). I suspected something is wrongmaybe he have changed my username pass. Luckily he hasn’t although later I was not able to login :). He just testedthe new exploit below on pc-freak. Luckily I have such friends to remind me of a problems very early.I guess this exploit is going to put a lot of havoc in the Linux world. But yeash that’s life. Today Plamenkothe guitarist came home and was my guest. We have downloaded some of hi (mountain clips) and put them on DVDs.Later I drinked a coffee with arkadietz and static. They were in an euphoria because of this exploit.I advice everybody there to patch as fast as possible or expect surprises :)END—–
Tags: allows, attackers, kernel, LOCAL, serious, vulnerability
Posted in Computer Security | No Comments »
