htop, an interactive process viewer for Linux. It is a text-mode application (for console or X terminals). It is a powerful alternative to using the top command. Here is a little script to install htop, which can easily be applied to any number of other simple installs too. #!/bin/bash cd /opt # Download and install if [ $(arch) = “i686″…
Read More »If you are using something like imap.mail.yahoo.com or outlook.office365.com and would like to add a firewall rule to open the appropriate IPs to access could be quite a challenge. These IPs seem to change often. Here are a couple of command lines that may help sort through this mess. Typically, a simple command would be executed with results. nslookup outlook.office365.com…
Read More »Rootkit Hunter is a security monitoring and analyzing tool for POSIX compliant systems. Well, at least that is the official definition for this utility. From the man pages, rkhunter is a shell script which carries out various checks on the local system to try and detect known rootkits and malware. It also performs checks to see if commands have been…
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One of the MySQL servers was running out of space, it turned out to be over 7GB of bin logs filling up the hard drive rather quickly. Since this server is not replicating, then a few modifications to the my.ini or my.cnf file will disable this “feature”. Edit the my.cnf file. Yours may be somewhere so search for it with…
Read More » Every now and again a MySQL root password may have been forgotten or undocumented along the way, but that does not negate the need to access the MySQL server. There is a way to gain access to the MySQL server to change the password for root and eventually log in as root. Applies to: CentOS / RHEL / Scientific Linux…
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Using a CentOS 7 box running a Plex Media Server and an Apache reverse proxy on the same box without a domain name and only an IP address and after much trial and error, a working Apache configuration file finally materializes. The goal was to eliminate the need of typing the port number to access the Plex Media Server web…
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After a few years and many yum updates later, the hard drive begins to fill up. There may be many versions of the Linux kernel. Many of which may be removed and to do this the yum-utils package is needed. Pre-CentOS 8 Install the yum-utils package. yum install -y yum-utils Check your running version. [root@server01 opt]# uname -a Linux server01…
Read More » After creating a usable MySQL database backup script and having tested it throughly, I put it in the /etc/cron.daily directory where I had expected it to run automatically. I had even tested it from that directory manually with success. After some time had past, I realized that the script was running as it read in the logs; however had only…
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Great, so you have another service running on your Linux box. It’s main purpose is to intercept an email, run rules against it, and either mark it as spam or not. Either way, it sends the email through and you still have to deal with the message on the email client. From the email client, you could make the necessary…
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SpamAssassin is an e-mail spam filter which uses content-matching rules. For this install, CentOS 6.6 (64-bit) and Sendmail are used. Enable EPEL repository. One way is to download and install the EPEL repository. wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm yum install -y epel-release-6.8.noarch.rpm Another is to edit the /etc/yum.repos.d/epel.repo file and change enabled=0 to enabled=1 under the [epel] section. [epel] name=Extra Packages for Enterprise…
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OpenVZ (Open Virtuozzo) is an operating system-level virtualization technology based on the Linux kernel and operating system. OpenVZ allows a physical server to run multiple isolated operating system instances, called containers, virtual private servers (VPSs), or virtual environments (VEs). OpenVZ is similar to FreeBSD jails and Solaris Containers. Download the OpenVZ repo. wget -P /etc/yum.repos.d/ http://ftp.openvz.org/openvz.repo Import OpenVZ GPG key….
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Rainloop is an attractive webmail with a nice clean modern feel to it. After following several different installation procedures, I finally got a working copy. Assumptions: Apache has already been installed. Sendmail or Postfix is already installed correctly. Install Rainloop mkdir /var/www/html/rainloop cd /var/www/html/rainloop curl -s http://repository.rainloop.net/installer.php | php find . -type d -exec chmod 755 {} \; find ….
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Speedtest.net is a go to site for testing Internet speeds, which is usually accomplished through a web browser. There is a command line utility that offers the functionality without the need of a GUI or the web browser. cd /opt wget https://github.com/sivel/speedtest-cli/archive/master.zip unzip master.zip cd speedtest-cli-master/ chmod +x speedtest_cli.py ./speedtest_cli.py mv speedtest_cli.py /usr/bin/ To run the utility, type speedtest_cli.py. Here…
Read More » Have you ever wondered at what speed your network is really operating? There are several programs and utilities that are readily available. I have tested a couple, however, this one seems to be the easiest and very efficient. This was tested on a CentOS 7 server. From the server, which in this case is 10.10.10.10. nc -lk 2222 >/dev/null From…
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One approach to adding space to an existing Linux hard drive that is using Linux LVM is to add space to the drive. This can easily be accomplished in VMware. This has been tested using VMware Workstation 9.0 for Windows with CentOS 6.5 (minimal install). To demonstrate a before and after, here are a few commands that can be used…
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A bug which could allow for arbitrary code execution has been discovered, Red Hat alerted, and patches exist. So, I simple yum update should take care of things. However, Red Hat offers command line arguments which may be used to test for the vulnerability. Using the command issued below, different warnings may appear, however, the following result is one of…
Read More » An anoyance with cloning a Linux virtual machine is that the /etc/sysconfig/network-scripts/ifcfg-eth0 file may contain a UUID and HWADDR which can be removed and the /etc/udev/rules.d/70-persistent-net.rules can be deleted or zero’ed out. So, here are the steps I use to create a “template”. Remove the UUID and HWADDR lines from the /etc/sysconfig/network-scripts/ifcfg-eth0 file. > /etc/udev/rules.d/70-persistent-net.rules to zero it out. Run…
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