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Rebuilding a corrupted RPM database

A few days ago one of our customers reported that he couldn’t install any packages using yum command using CentOS Linux. After investigating I found the RPM database was corrupted. This is a very common issue on CentOS and RHEL servers. CentOS and RHEL servers use rpm to manage package installation, remove and upgrades. If the rpm database is corrupted in…

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Script timed out before returning headers: index.php

Script timed out before returning headers is one of the most common errors you will see while developing web applications, or if you are a system administrator. It can be caused by many different things, but it’s always related to timeout configurations (or a very bad programmed script). How to fix Script timed out before returning headers error?…

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How to install NTPD on CentOS Linux – CentOS ntp installation guide

How can I install NTPD on CentOS Linux (desktop and servers)? You can do it easily using NTPD, NTP means Network Time Protocol. NTPD is a system daemon that helps servers to keep their date and time syncronized with the global CentOS NTPD servers. This tool is available for desktop or servers running any kind of Linux distribution. In…

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How to fix disk quotas on a cPanel server

On this post we will show you how to check the health of your system quotas, you will also learn how to fix disk quotas on cPanel systems. As it’s very common to face disk quota issues running WHM/cPanel software. Fix disk quotas on cPanel The first thing that you must do while analyzing quotas on a new…

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Error 421: too many concurrent smtp connections

On high traffic email servers you may see this kind of errors, it’s very normal in some situations when your users use lot of email. It basically means that there are a lot of open SMTP connections (incoming and/or outgoing). The exact error message may be something like: 421 Too many concurrent SMTP connections from this IP address; please…

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How to increase /tmp partition size on cPanel

Yesterday we published a security tutorial called: Secure /tmp partition on cPanel. While that way to secure the /tmp partition is fine, the script used by cPanel (/scripts/securetmp) has a problem that often affects many system administrators and developers. The problem is simple: cPanel allocates a small space size for the /tmp operations, and lot of times you…

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Secure /tmp partition on cPanel using /scripts/securetmp

On Linux systems there are a few temporal directories used for storage, like /tmp, /var/tmp and /dev/shm. This directories are used to store temporary files from different services such as Apache, MySQL, etc. However, sometimes this directories are also used by crackers and script kiddies to store malicious/malware and virus executables. This malicious scripts can be an open…

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