In our example we take "sound.mp3" and convert it to .wav. Generally Asterisk for its wave needs one audio channel (-ac 1) / mono and 8000hz (-ar 8000) instead of the standard CD/MP3 of 44100hz. Here is the command to convert into Asterisk .wav format: ffmpeg -i sound.mp3 -ac 1 -ar 8000 sound.wav Errors Asterisk may give you if the format is wrong: -- Executing [91781891@cme:3] Playback("SIP/234-000........

Make sure this makes sense for you but I've started to block a lot of commercial Cloud services and easily accessible providers as they are a very high source of abusive traffic. The cost savings for a lot of organizations are huge, as you now have less bandwidth usage and less resource usage from garbage/bot/malicious traffic. This mainly works for when you can be reasonably sure that your audience has no business visiting your service(s) from freely accessible commercial IP ........

Sometimes users take their removal drives and unplug and replug them to test what happens during the failure of a disk. However, this breaks things quite badly due to the /dev/mapper in LUKS not coming back online due to it not being closed. In other words, generally with non-encrypted drives the process is smooth but when encrypted you may want to follow a strategy like this: We can see below that both disks are unavailable as they were physically remov........

Have you ever tried mounting a partition that you exists but you get this error? mount: /mnt: can't read superblock on /dev/sda1. The superblock in this example was bad because the physical disk had corruption and bad blocks/sectors. However, the data was generally accessible and you can always try this trick below (with caution and no warranty). This is specifically for filesystems that place superblocks in multiple locations, which........

A lot of companies are unsure which solution to choose and many may not be aware of Docker Swarm as an alternative to Kubernetes. One thing that many Sysadmins find is that Docker Swarm is simply easier, quicker to setup and maintain by far than Kubernetes.........

A lot of developers want to go to 3.11 because of the speed improvements, but most distros never have the latest Python version. Using the deadsnakes third party repo is the easiest way aside from compiling it yourself (which is safer and recommended): Step 1 - Add the repo apt-add-repository ppa:deadsnakes/ppa If you get an error about requests then install it:........

So say you happen to have 2 NICs of the exact same chipset, they will generally show up as the same name, with possibly a different revision in lspci. Normally this is not an issue if you have a server with 4 NICs, generally the eth0 to eth3 appears from left to the right (or right to left on some vendors) so it doesn't take much figuring out. Generally if you have different chipsets for different NICs, it should be easy to know which one is eth0 or the first NIC in the OS.........

Bonding is an excellent way to get both increased redundancy and throughput. It is similar to the "Network Teaming" feature in Windows. There are a few different modes but we will use mode 6, I think it's the best of both worlds, as it is not just a failover, but it provides round robin, so you will get redundancy and load balancing. So if you have a 1G single port, you will have a combined throughput of 4G at this point. Just bear in mind that the true thr........

If your audio is not working and you got this in your syslog: pulseaudio[13710]: [pulseaudio] sink-input.c: Failed to create sink input: too many inputs per sink. The issue is generally caused by too many audio inputs, or in other words you have too many applications that are hooked into pulseaudio. An easy and notorious offender is by having dozens of Firefox browser tabs open. Solution: Close all of your Firefox and the problem will........

The Best Docker Tutorial for Beginners We quickly explain the basic Docker concepts and show you how to do the most common tasks from starting your first container, to making custom images, a Docker Swarm Cluster Tutorial, docker compose and Docker buildfiles.........

It took a lot of fiddling to make a Huion Kamvas 13 Pro work in Linux but it simple once you know what to do. Don't bother searching as it is unlkely there is a guide out there that will actually make your tablet work. It mainly comes down to the fact that the hid_uclogic kernel module is buggy or doesn't support MANYof these wacom based/Huion tablets properly. What was happening with me is that Ihad the Kamvas 13 Huion setup as a secondary screen/monitor.&nb........

The idlepc value is very important to dynamips and it is both image and often CPU dependent. There is no "magic"value that will work for all images and all CPUs so this is why I'll show you a quick and handy way. Also don't be disappointed, some values do not work well but idlepc gives you several. For example in my example below #6 didn't help at all but #7 got me down to about 6% CPU from 99-100%. *Befo........

This assumes your system is a fresh and normally working install. What often happens is that many new devices have multiple audio outputs which are generally analog and HDMI/Digital out. Sometimes the OS defaults to the wrong one that you didn't want. For example if your sound is supposed to play over the HDMI, perhaps the output is set to analog or vice versa.........

You should only get this if you are using a Pentium II or something really old. The problem here is that newer kernels than 2.6 don't have true i386 support even if you tell it to compile as i386. It will still include features like cmov that break older computers from being able to work. Generally for very old computers like above, you need to use a 2.6.x kernel and of course make sure it is i386 and all the binaries are as well. ........

apt install software-properties-common add-apt-repository ppa:deadsnakes/ppa apt update apt install python3-pip apt install python3.7 curl gnupg python3.7-dev git ln -s /usr/bin/python3.7 /usr/bin/python3 pip3 install numpy keras_preprocessing curl https://bazel.build/bazel-release.pub.gpg | sudo apt-key add - echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel........

I used to believe that for Desktops especially that the "ondemand" CPUfrequency changing that kernels included with Ubuntu and Debian based distros have would be sufficient for snappy performance. However, you can feel the lack of performance on the fastest computer if you have ondemand. A lot of times even under high load 100% of your CPUfrequency in MHz will not be used. For example a 2.8Ghz CPUmay only run at 1.8MHz or even .9GHz. Now........

I don't consider a lot of these "extra" kernel modules "nice to have" as they often contain drivers for essential items like your soundcard, your NIC and many other devices that may not work. Sometimes you may find that "sound" or "ethernet" worked before a kernel/OS upgrade and now in the new version they don't. Often it will be because you need to install the "extra" kernel modules. One other weird thing is that sometimes........

systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system. The key commands or arguments you will use with systemctl are the following: Unit Commands: list-units [PATTERN...] List loaded units &nbs........

Sep 12 18:16:25 vps pluto[7299]: ERROR: asynchronous network error report on eth0 (sport=500) for message to 192.5.6.2 port 20640, complainant 192.5.6.2: Connection refused [errno 111, origin ICMP type 3 code 3 (not authenticated)] Some say changing the "leftprotoport=17/%any" will fix this but I have not found this to be the case. Essentially it means at least one end is blocking the ipsec packets. Sometimes the %any allows an alt........

When things go wrong your video is basically unplayable or the first video plays fine and then freezes when moving on to the next. Generally if both videos weren't produced with the exact 100% same settings you will have issues. You can try the basic concat but it often won't work right. Solution for me: My example uses 3 videos in total so "n=3" and a=1 to include audio. ffmpeg -threads 12 -i file1.mp4 -........

*Update so this doesn't work it must be something to do with the path of nfs or something else but the installer fails with "Installer crashed" at the end whereas with the CD/USB it works. This assumes you've already installed and configured a separate PXE/DHCP server somewhere else and your /tftpboot directory is setup. This is for Linux Mint 18.1 but generally applies to most versions although you may have tro change things like "casper"........

Motherboard: Gigabyte GA-3CESL: http://b2b.gigabyte.com/products/product-page.aspx?pid=2658#dl Dell Part Numbers for the motherboard: R1232 R1232L R2232S SERVER MOTHERBOARD GENUINE 408P9 CN-0408P9 GA-3CESL Manual Download here RAMSlots: 16 (8 controlled by each CPU) RAMType: DDR2 ECC 5300P........

Failed to load VMMR0.r0 (VERR_SUPLIB_OWNER_NOT_ROOT) In most cases the error above is useful, it generally means /usr or /usb/lib or /usr/lib/virtualbox is not owned by root and this is the cause of the error. Solution sudo chown root.root /usr/lib........

This happens because of a permissions or ownership issue. Generally /var/lib/mysql should be all owned by mysql.mysql (check that). To fix it use chown -R mysql.mysql /var/lib/mysql Also make sure the files are at least readable and writable by mysql (eg. 700).........

Here's a proven example of what a bad hard drive can do, it was technically functioning OKin a RAID array but the system became extremely low and the load become high and IOWAIT was even higher and I always thought it was a bad application. The truth is that this failing 1TBHitachi has slowly gotten worse and caused huge slowdowns, (eg. 100% load on Thunderbird waiting for e-mails to load etc..). After swapping it out, tabs change instantly, emails are not lagged, and........

I backed up everything in the /mnt/sd_card directory thinking that some dataloss could occur for some reason but purposely left my microSDHC unbacked up thinking that "it won't touch that since it's external" and Samsung's and other manufacturers website even say this (that it won't be affected and not to worry etc). Apparently I was wrong, my microSD was "undetected" and asked to be formatted after the upgrade (there goes 3-months worth of family photos). No........

For years I've always built cheap systems believing that there is little difference in more expensive components when it comes to reliability and quality, I generally believe this still except for Power Supplies. I've always bought cheap cases with nice sounding 350-550W stock/cheap/crap power supplies and haven't had any issues for the most part until recently. One such case is an NGEAR case with a 550W Optimax power supply, I always read that these supplies don't produce the........

I really am a Linux fan but my comments here may not show it. Although I'm quite familiar with Linux CLI to administer servers, I find Linux GUI OS's like Ubuntu at times very clunky. This is partially because there's no such thing as a "self-made" Linux from scratch where the UIwas designed by a single team. Linux is made up of several different projects that are generally completely separate and this lack of integratiion is a key issue that makes things f........

I wanted to Import/Use a .vmdk hard disk image file from VMWare. Generally you can just "point" VirtualBox to it and use it and it will work but I found an exception. One of my Centos 4.4 x64 images wouldn't boot. I had two copies, an older one and the newer one. The older one booted as normal (once I changed the VirtualBox driver to IDE from SATA). The newer one stopped at the "GRUB loading" message no matter what I tried. As far as........

I am a huge fan of Linux and the idea of OpenSource but I've said it many times, there are still hurdles in today in 2010 for Linux as a Desktop. Linux is still intended for servers at its very core. This can be changed succesfully though, as Apple has shown us with Mac OS X based on FreeBSD. Half of the issue is lack of driver support and the other half is the Linux Kernel and Window Manages, KDE and GNome still both don't cut it (but they're getting closer). I'll........

I'm guessing RAM manufacturers forgot they're not the oil/gas companies and are playing games. It was just a year ago when I was buying 2GB sticks as low as $20 CAD! Now the average price is $50 CAD. What happened to Moore's law when it comes to pricing for RAM? Every other piece of hardware generally has been coming down without exception. ........

CDR Manufacturers - Why is so much media bad?I have searched for good media and tried many kinds for years. I guess I'll try to summarize my findings and conclusions. Dye is irrelevant, dye of any color can be good or bad, it more likely depends on the manufacturer. Speaking of manufacturers, the name at the top of the disc means nothing. For example, Memorex along with any other 'brand' is actually always made by another manufaturer including CMC Mag........

Other Security Web SitesSeveral websites actively track security issues. This list provides you with the major providers of security information on the Web. Many of these organizations also provide newsletters and mailings to announce changes or security threats: Center for Education and Research in Information Assurance and Security (CERIAS) CERIAS is an industry-sponsored center at Purdue University that is focused on technology and relate........

This really is a difficult and confusing process for non-Mandarin speakers, but here's what I've done and learned so far: You can purchase an "M-Zone" China Mobile pre-paid SIMCard from almost anywhere but I tried to purchase mine from Suning (a large electronics dealer) hoping they would be able to help me or answer my questions but my plan didn't work out at all. At Suning once I found someone who spoke some English they gave me the 55 RMB M-Zone China Mobile P........

I've tried to find a good sensible solution to cluster with and each technology has it's pros and cons and there is no perfect solution and I've found a lot of "exaggerations" in the applications, benefits and performance of these different filesystems. DRBD I first started off with DRBD and Ihave to say it does live up to the hype, is quite reliable (although it can be annoying to match up the kernel module and user applications since they must match and whe........