This guide assumes you have a working Postfix server and want it to sign with DKIM. There are a few things we have to understand to make all of this work though, which require you to be familiar with DNS as well. 1.) Install OpenDKIM apt install opendkim systemctl enable opendkim 2.) Edit /etc/opendkim.conf Syslog yes SyslogSuccess yes Mode&nbs........

This seems to happen in many different drivers but it happened more often in newer versions such as 530 vs 525. Then nvidia-modeset goes to 100% There are many reports of this appearing since driver 4.70 and I can confirm I've seen this in various machines. https://forums.de........

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........

This will be the goto to help solve e-mail delivery issues and talk about many practical issues that happen between developers, admins and scripts that send e-mail and do things that may not be acceptable or cause deliverability problems. Sendmail Stuff Edit /etc/mail/sendmail.mc The problem is that if you send directly out from the server using the mail function, the Return-path of the e-mails will be username@thehostnameoftheserver.com. Let........

The easiest way for the current running kernel is: update-initramfs -u -k `uname -r` You could change -k to a specific kernel name if for some reason the current is not running (eg. if you are chrooted or in recovery mode). If you want to update all kernels then use "-k all" update-initramfs -k all -u update-initramfs: Generating /boot/initrd.img-5.4.0-162-generic........

qemu-img can convert many formats. Here is an example of how to convert different images to different formats for QEMU-KVM The example above converts a raw windows2019.img file from QEMU to a Virtualbox .vdi qemu-img convert -f raw -Ovdi windows2019.img windows2019.vdi -f raw = this means the format of the source image (instead of raw it could be vdi, vmdi, qcow2 etc..)........

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........

This problem has been around forever, Linux seems to think it is fine to use the r8169 driver for an r8168 NIC but this often causes problems including the link not working at all. In my case ethttool shows the link up and detected but it simply does not work especially on a laptop that has been resumed from suspension. Sometimes it takes several minutes for it to work or to unplug and replug the ethernet. Here is the solution: Install th........

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........

If you've just installed VBox and it is not starting or working, the most common problem is usually that you don't have your kernel source installed, which means there is no kernel driver for vbox so it can't work. You may get an error that says "Kernel driver not installed" in your Virtualbox. So the first thing you should do is install your kernel source by running this: sudo apt-get install linux-headers-`uname -r`........

SSH helps keep us secure in many ways, one of those is the host-key fingerprint which is unique. If you have been connecting to an SSH server that you've made no changes to and suddenly ssh warns that the key doesn't match then you have a problem. But how about connecting to an existing server for the first time on a new machine or client? A lot of new clients calculate it using an SHA256 hash but it is not as easy on your host machine to produce the sam........

Install Errors on Version 12: This error happened on QEMU emulator version 2.11.1 pve-qemu-kvm_2.11.1-5 on Proxmox/Debian but installing on QEMU.12 on Centos 6 did not produce the error. *Update it is not related to the OS or QEMU version. This happened in Centos 6 too after a second install. What really causes this even though you successfully install........

The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs. qemu-kvm command: /usr/libexec/qemu-kvm -version QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard ........

sudo apt-get install libcurl4-openssl-dev git build-essential autotools-dev autoconf libcurl3 sudo apt-get install libcurl4-gnutls-dev git clone https://github.com/wolf9466/cpuminer-multi sudo apt-get install cmake libpthread-* libmicrohttpd-dev libssl-dev libhwloc-dev git clone https://github.com/fireice-uk/xmr-stak-cpu.git make install cd bin chmod +x xmr-stak-cpu ./xmr-stak -O xmr........

#mount the VCSA DVD mount /dev/sr0 /mnt/cd #alternatively you could mount the iso directly mount -o loop vcsa.iso /your/mount/path #for this purpose we are using the CLI installer on Linux cd /mnt/cd/vcsa-cli-installer/lin64 #no it's not going to be that easy you can't just run vcsa-deploy like that you need to use a template or configured .json file ./vcsa-deploy Usage: vcsa-deploy [-h] [--version] [--supported-deploymen........

The reason for this article is because a lot of us don't physically see our hard drives they are often remote in a datacenter etc and the actual serial number we see in SMART is not enough to check for some manufacturers. A good example is our first one the Toshiba === START OF INFORMATION SECTION === Device Model: TOSHIBA DT01ACA200 Serial Number: 33FMDW4AS........

The main issue is it looks like Java is not configured to accept the invalid ssl cert that is coming from the download location. Exception in thread "main" java.lang.RuntimeException: javax.net.ssl.SSLException: java.security.ProviderException: java.security.InvalidKeyException: EC parameters error export ANDROID_HOME=/home/user/Downloads/tools/ Conversations-master$ ./gradlew Downloading https://services.gradle.org/distributions/grad........

To get the first X letters of a word: It's very simple you can just pipe it to head with -c 1 (gives the first letter and so on) -c2 (2 gives the first 2 letters). echo "dsjfsdlksjdklf;jlsd;kflasdj;kl"|head -c 2 Returns ds To get the last X letters of a word: Now we use tail with -c but it works differently. ........

When using the .sh script the rendering doesn't work after an upgrade of related packages to kdenlive. kdenlive (kdenlive:amd64 (4:17.04.1+git201705191233~ubuntu16.04.1)) with affine or composite transitions was fine but is now broken during the time of transition it is just a white screen. The previous version was fine: kdenlive:amd64 (4:17.04.1+git201705191233~ubuntu16.04.1 But now I can't find it or install it:........

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 -........

#if you have nvidia make sure you install the nvidia-cuda-toolkit so hardware acceleration can be used wget http://ffmpeg.org/releases/ffmpeg-3.3.2.tar.bz2 tar -jxvf ffmpeg-3.3.2.tar.bz2 cd ffmpeg-3.3.2/ ./configure --disable-yasm install prefix /usr/local source path ........

I keep reading these drives are slower, but they are cheap and still SSDand work very fast for my needs. As you can see the sequential read is 481-491MB/s, if I put them in MDADM RAID10 mode (normal RAID1) they should give me well over 900MB/s and with redundancy and being very cheap for what they offer. [1232206.315622] scsi 8:0:1:0: Direct-Access ATA ADATA SU800&........

This command in Debian/Ubuntu/Mint will get everything need installed for most Java based KVM viewers: sudo apt install icedtea-netx The following additional packages will be installed: ca-certificates-java icedtea-netx-common openjdk-8-jre openjdk-8-jre-headless It seems every other updated version of Java or Icedtea breaks things and I will save the frustration of Java for another post.........

The solution was to reinstall the vbox dkms package and do a manual modprobe of the modules it makes. I never sorted out the unable to start due to the USB issue, I did have the guest additions installed but the only way to boot was to change the pointing device from USB to PS2 and then to disable the USB controller (if your pointing device is set as USB, disabling USB will not work because it will re-enable by default when it sees your pointing device is USB, this is w........

#from epel repo yum -y install opendkim chkconfig opendkim on cd /etc/opendkim/keys opendkim-genkey -vd mail.server.com opendkim-genkey: generating private key opendkim-genkey: private key written to default.private opendkim-genkey: extracting public key opendkim-genkey: DNS TXT record written to default.txt ........

The solution is to run '/etc/init.d/vboxdrv setup' and sometimes happens when upgrading VBox and the kernel modules don't get upgraded with it. Sometimes the above doesn't work until you reboot because sometimes other unknown processes (even the file manager possibly) may be locking the old module from being unloaded. Failed to open a session for the virtual machine XP. The virtual machine 'XP' has terminated unexpectedly during startup with exit code 1.........

mytop-1.4-2.el5.rf.noarch from rpmforge has depsolving problems --> Missing Dependency: perl(DBI) is needed by package mytop-1.4-2.el5.rf.noarch (rpmforge) solution: #disabling excludes is required on CPanel type boxes which exclude most updates including perl-DBI yum --disableexcludes=main install perl-DBI mytop-1.4-2.el5.rf.noarch from rpmforge has depsolving problems --> Missing Dependency:........

Error: Package: php-Monolog-dynamo-1.7.0-1.el6.noarch (epel) Requires: php-aws-sdk Error: php-pecl-zendopcache conflicts with 1:php-eaccelerator-0.9.6.1-1.el6.x86_64 Error: php-xcache conflicts with php-pecl-apc-3.1.9-2.el6.x86_64 Error: php-pecl-zendopcache conflicts with php-pecl-apc-3.1.9-2.el6.x86_64 Error: Package: php-horde-Horde-Vfs-2.1.2-2.el6.noarch (epel) &n........

This is useful for developing a lot of applications, I'm putting it here to keep it handy for myself and hopefully others: Choose CountryCanadaJapanUnited StatesUnited KingdomAfghanistan........

The example below converts youvm.img into a vdi. The -O vdi specifies the new format will be vdi but you can use any other valid formats/vice versa. qemu-img convert yourvm.img -O vdi yourvm.vdi This is very handy for those who need to switch between virtualization technologies.........

I dread updating the kernel and rebooting to find the Ubuntu graphics aren't working and you have to manually intervene. This is usually because Ubuntu for whatever reason didn't update the drivers you need (eg. the manually compiled Nvidia Kernel driver that MUST be recompiled for each and every kernel update unfortunately). The most common reason may be that "linux-source" hasn't been installed automatically on my system. I tried to manually reinstall the........

Visit http://linux.softpedia.com/get/Programming/Interpreters/Android-32340.shtml Basically copy and paste all of that below and you'll have installed and started the Android SDK before you know it. wget http://dl.google.com/android/android-sdk_r12-linux_x86.tgz sudo apt-get install openjdk-6-jre openjdk-6-lib openjdk-6-jre-headless tar -xvf android-sdk_r12-linux_x86.tgz cd android-sdk-linux_x86/tools ./android........

I don't expect this to be solved soon but some of Yahoo's DNS servers are out of whack. I changed the IPs of some nameservers of some domains and now most Yahoo users can't e-mail to those domains! As you can see below by the "No MX or A records for mychangedomain.com", now Yahoo's DNS/mailserver DNS cache is wrong. You would think they would at least have cached the old incorrect records, but instead for some reason their DNS cache has no entry and doesn't seem........

The first thing you need to remember is not to check from the same host/server itself. This is a silly mistake I made, the reason is that many mailservers and especially postfix are configured to allow relaying from the localhost/same host. If you do that you'll get a false positive. *Make sure you test from another host/system than the mail server itself! telnet yourmailserverhost.com 25 220 Courier (FreeBS........

Go into the directory for your Virtual Machine and delete all ".lck" directories. rm -rf *.lck After that your server should boot.........

I've only used it on Centos, soI thought I'd make a quick Debian guide: Install the DRBD Package apt-get install drbd8-utils Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: libswfdec-0.8-0 Use 'apt-get autoremove' to remove them. The following........

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've never understood how to enable and disable services for different run levels in Debian based distros, it's just weird, annoying and doesn't make sense. I much prefer chkconfig from RHEL. Just install the package called 'rcconf' and be done with it. rcconf makes things easy for you. apt-get install rcconf Reading package lists... Done Building dependency tree Reading state information... Done........

The last transfer I was able to do was 16.77GB according to rsync's output and it worked fine. 16.77G 100% 10.66MB/s 0:25:00 (xfer#17484, to-check=234753/256249) But on a file over 17GB (gigs) it stalls. Trust me, it really is stalled, it's been about 8 hours with no progression from that point for some reason. 17.24G 54% 10.65MB/s 0:22:07........

In Debian based distros: apt-get install jabber Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: fakeroot dkms Use 'apt-get autoremove' to remove them. The following extra packages will be installed: jabber-common The following NEW packag........

Yes, Iadmit I finally got bitten by the hype as much as I can usually see through it all. Keep in mind this review is of the "stock" phone, no jailbreaking yet which is what really unleashes the customizability and whyI bought iPhone. I had better things to say about this phone before buying it, and it is a great phone, perhaps the best on the market by far, if not because of the Mac OS port onto the iPhone and all the apps, etc, etc. With that said........