Even today we see a lot of servers that have different services and ports open for rpc and this creates not only potential inward vulnerabilities but perhaps more common, the abuse of your network resources in reflective rpc queries. To stop this problem, you should disable and remove all services relating to rpc or at least block all relevant ports for the service. Surprisingly, there are still some providers and OS installs in Linux that install these services and leave them........

This seems to have changed for RHEL 8 where a normal dracut to update your initramfs creates a system that only boots for the running kernel. For example if you have Kernel 5 and then chroot into a RHEL 8 variant which uses kernel 4.18, and run dracut, it seems that by default the system will be unbootable. It is also the case that if you move your RAID array or drives to another server that it will be unbootable, because dracut seems to only include modules needed for the curre........

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 you are using mint, delete the preference that stops snap from installing (as it is required for lxc) sudo rm /etc/apt/preferences.d/nosnap.pref 1. Install lxd: sudo apt install lxd Issues install lxd or errors? Click here Debian at this time does not have lxd so you'll need to use snap: sudo apt in........

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.........

Why choose OpenVPN instead of a firewall appliance? OpenVPN can be a reliable and easy replacement for traditional hardware or just be an additional tool that your company uses so that the firewall can focus on its job rather than acting as a VPNappliance at the same time. When comparing OpenVPN with traditional firewal........

In QEMU 4 or higher you can no longer use the normal "-soundhw ac97" flag and it is much more complicated but here is a simple copy and paste on Linux that will just work: -audiodev you have to use -audiodev to specify the driver and id driver=pa id=someid -device you have to specify the same audiodev id you used in -audiodev and driver -audiodev driver=pa,id=pa1 -devic........

If you can print other PDFs but not a particular one it is very likely that the PDF size is A4 (the longer, skinnier Asian paper size) instead of the North American letter size ( 8.5" x 11"). This breaks printing in most cases. Or it may print if you find a program that ignores the size issue. Here is an example of an A4 being rejected by a printer in Ubuntu Linux via CUPS Cannot print PDF CUPS Samsung C460: Processin........

initiator = client target = server These are the first concepts you should understand which is that in iscsi essentially the "initiator" is the client and the "target" is the server. iSCSI is derived from the old fashioned SCSI that us oldtimers grew to love. The "i" stands for Internet and the SCSI stands for "Small Computers Systems Interface" (SCSI). iSCSI Target (Server)Setup targetcli is the pac........

Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments. Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........

Proxmox at the root of your storage creates and "images"and "templates/iso" folder for VM images and iso's respectively. It ignores files in any other location.........

yes it does create its own json ============================================ cat /tmp/vcsaUiInstaller/ovftool-20180809-175238948-20180809-175603497.log |grep -i json 2018-08-09T17:56:04.238-07:00 verbose OVFTool[30966] [Originator@6876 sub=Default] Manifest file entry: SHA1(VMware-vCenter-Server-Appliance-6.7.0.12000-8832884_OVF10-file1.json) = 1deb658c724767697587d5909c4051c01813e6a1 --> ........

Sometimes if you have a very basic configuration OpenVPN on the client side for some reason sends all traffic to the OpenVPN server IP through the tun0 which is of course impossible and creates a block or routing loop. This is because you need to use your normal ISP/LANgateway to hit the OpenVPN server if it is remote/offsite as is usually the case. So if you are connected to the OpenVPN through say a tun0 device and your routing is set to connect to the OpenVPN&nbs........

ValueError: new value non-existent xfs filesystem is not valid as a default fs type Pane is dead From what Iread this is misleading and has to do with the fact that the initrd and kernel are mismatched. This is a hard situation because for some older hardware Iam using the Centos Plus kernel which has modules that Irequire for an older server/NIC. This seems to have cropped up in the past few months and there is no simple fix........

Done on Centos 7.3 very important as clearly based on older guides it was a lot easier and more simpler! Hint do not use grub2-install! If you have trouble booting after this check this CentOS mdadm RAID booting/fixing guide. One huge caveat if you are an oldschool user or sysadmin who has avoided UEFIbooting The nor........

Tired of checking iotop and seeing that your drbd partition is using 99.99% of io all the time and finding your drbd device performs slow in general? This is especially an issue in versions of DRBD in the 8.3 tree in particular one documented case is on "8.3.13" but it likely applies to other devices. The symptoms are that resyncing is fine and normal but any reasonable amount of activity is very slow and lagged and creates a high server load and con........

It's a basic script that reads the file "ips.txt" in the current directory and then creates a corresponding ifcfg file     #!/bin/bash GATEWAY=192.168.1.1 NETMASK=255.255.255.0 device=eth0 counter=0 for ips in `cat ips.txt`; do........

Download the latest from Adobe's site and unzip it, enter the directory it creates and type the following: sudo cp libflashlayer.so /usr/lib/adobe-flashplugin/ sudo cp -r usr/* /usr........

cp -L index.php index.php-2013-08-21 The -L switch is what you need because it's a huge issue if you think you've copied a file for backup purposes but it really just creates a symlink to the original file.........

qemu-img create -f qcow2 isotest.qcow2 10G The above creates a "qcow2" format image called "isotest.qcow2" that is 10GB in size. If you want to preallocate all of the space for increased performance do this: qemu-img create -f qcow2 isotest.qcow2 -o preallocation=full 10G It is controlled with the preallocation=full option, of course by default this is set to off........

foreach ($_POST as $key => $value) { if ( $key != submit ) { $values.="$key=$value<........

CREATE TABLE articles_backup LIKE articles The code above creates a new table called "articles_backup" which has the exact same structure and attributes as the original articles table. CREATE TABLE articles_backup SELECT * FROM articles; The above code does the same thing as the first example, BUT it also copies all of the data.........

It's really silly how DA doesn't enable SSL by default but is otherwise a stable, fast and secure control panel. Here's a copy and paste way of enabling SSL for Directadmin in just a few seconds: *setup SSL openssl req -x509 -newkey rsa:1024 -keyout /usr/local/directadmin/conf/cakey.pem -out /usr/local/directadmin/conf/cacert.pem -days 9999 -nodes That creates the public certificate and private key pair in the location Directadmin expects to fi........

dd if=/dev/sda of=/dev/null creates ever increasing load every second. After minutes the load has moved up to 4.79 I've tried with two different discs in my system. I wonder if it's a delay or problem with the SATA bus because one drive I have connected has recently failed. I notice when drives fail that you get some IO/blocking issue when they don't respond properly. Yes I believe it was, because here's the same disc after removing the dead........

yum -y install vnstat chown nobody.nobody -R /var/lib/vnstat/ #replace venet0 below with your desired interface sudo -u nobody vnstat -u -i venet0 #edit: vi /etc/sysconfig/vnstat #VNSTAT_OPTIONS="-i venet0" # only use the sed below if you are using venet0 instead of eth0 or replace accordingly sed -i 's/eth0/venet0/g' /etc/sysconfig/vnstat [root@monitor]# yum install vn........

I think this will be useful to others because I have a server that kept crashing mysteriously during intense disk usage/RAID checks. It would only crash during the weekly RAID integrity check. ThenI noticed during a reboot that not all CPUs were being brought up, as a result this actually creates much higher temperatures with the output I got from sensors, just booting the system produced higher than normal temperatures. You can imagine that a full blown RAID check........

understanding /etc/aliases *remember to apply changes you need to run "newaliases" after editing /etc/aliases one thing I don't get is that it doesn't allow you to specify the whole e-mail address on the left-hand side eg: yourfullemail@domain.com: someotheremail@domain.com postalias: warning: /etc/aliases, line 109: name must be local (if you try the above) It works more like this: your........

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 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........

This is based on Debian Linux but should apply equally to any *nix distro. Install LUKS/crypt-setup apt-get install cryptsetup Setup your LUKS Partition Of course change /dev/md2 with whatever partition you intend to use LUKS on. cryptsetup --verbose --verify-passphrase luksFormat /dev/md2 You'll be asked to verify your decryption password twice *DO NOT FORGET THIS PASSWORD AS IT IS NOT RECOVERABLE!........

CREATE Database/Granting PrivilegesCREATE your first database Code: [code:1:0668cd8e74]CREATE database myfirstdb; [/code:1:0668cd8e74] CREATE a user for your first database This one creates the user 'sqladmin' and gives them 'usage' on your new database 'myfirstdb' Code: [code:1:0668cd8e74]mysql> GRANT usage on myfirstdb.* to sqladmin@localhost; Query OK, 0 rows affected (0.00 sec)[/code:1:0668........