Category Archives: Servers

Linux : Error failed dependencies updating kernel-3.10.63-11.el6.centos.alt.noarch

Having the following error trying to install/update kernel v3.10 from the Xen repository on CentOS 6? error: Failed dependencies: kernel-firmware < 3.10.63-11.el6.centos.alt conflicts with kernel-firmware-3.10.63-11.el6.centos.alt.noarch Well, you are probably trying to install using “rpm -i” command. You should use “rpm -Uvh” instead as followed : rpm -Uvh kernel-3.10.68-11.el6.centos.alt.x86_64.rpm kernel-firmware-3.10.68-11.el6.centos.alt.noarch.rpm

Linux : Error starting CSF /sbin/ifconfig (ifconfig binary location) -v does not exist!

Having such issue starting/stopping CSF on RHEL/CentOS 7? # csf -x *WARNING* URLGET set to use LWP but perl module is not installed, reverting to HTTP::Tiny You have an unresolved error when starting csf: Error: /sbin/ifconfig (ifconfig binary location) -v does not exist!, at line 2510 in /usr/sbin/csf You need to restart csf successfully to… Read More »

Linux : How to register RedHat Enterprise Linux

RedHat can be used upon a paid subscription. You have to register your system using the following command in order to use the Yum repositories : subscription-manager register –username <username> –password <password> –auto-attach If by any chance you ran that command in the first place but you had no subscription available in your account, your… Read More »

Linux : How to enable automatic updates with YUM on RHEL/CentOS?

Enabling automatic updates installation as they come available is quite easy. First, install the yum-cron utility as followed : yum install yum-cron Make sure the service is running : service yum-cron start Then enable the service on boot : chkconfig yum-cron on Optionnaly, you may want to exclude some packages from being updated, just edit… Read More »

Linux : error processing package nginx on Debian

Having this error trying to install Nginx on Debian Linux 8? dpkg: error processing package nginx (–configure): dependency problems – leaving unconfigured Errors were encountered while processing: nginx-full nginx E: Sub-process /usr/bin/dpkg returned an error code (1) This is a known behaviour if you have Apache or another Web server installed and running. The problem… Read More »

Linux : How to tune up receive (TX) and transmit (RX) buffers on network interface

Modern and performance/server grade network interface have the capability of using transmit and receive buffer description ring into the main memory. They use direct memory access (DMA) to transfer packets from the main memory to carry packets independently from the CPU. The usual default buffering values for regular desktop NICs are 256 or 512 bytes. High… Read More »

Linux : How to open a port on RHEL/CentOS 7 firewalld?

Here is how to open a port and make it permanent with the new firewalld on RedHat/CentOS Linux 7. You can statically edit /etc/firewalld/zones/zone.conf and reload the daemon, but the right way to do is the following. 1. Open the port by specifying the proper zone, port number and protocol. Unless you do not want… Read More »

Linux : Essentials MySQL Admin CLI commands

Here is a quick list of useful commands for any MySQL database administrator. Show the server full status : mysqladmin -u root -p extended-status You may also sort specific information with “grep” as followed : mysqladmin -u root -p extended-status | grep Threads Show the current running process and queries (remove “-i 1” to display… Read More »

VMware : How to enable and set SNMP community on ESXi

VMware ESXi hypervisor have some great SNMP capability, whatever to gather information status of your hardware, monitoring or statistic usage of your resources. Follow these easy steps to enable such feature. 1. Enable SSH from the vSphere client and connect to it using your favorite terminal application : Configuration tab > Security Profile > Services >… Read More »

Web : How to get Web site server information

Using cURL, you can easily grab some information about the server who’s running a Web site. To get all the possible information, simply use (replace domain.tld with the actual domain name) : curl -s -I domain.tld You can also can just output the server info like this : # curl -s -I microsoft.com|grep Server Server:… Read More »