From the blog
Fatal error: Call to undefined function mb_substr() Error
While working on a PHP based website, I found this error: Fatal error: Call to undefined function mb_substr(). This error is caused because mbstring PHP module is not loaded at the PHP general configuration files. Let’s see how to fix it. What causes Fatal error: Call to undefined function mb_substr() Error ? This error happens beacuse mbstring module…
Read More »How can I automatically run scripts at boot time in Centos 7?
One of the big changes CentOS introduced on version 7 was the lack of native execution for custom scripts to boot from /etc/rc.d/rc.local file. /etc/rc.d/rc.local was one of the most classic ways to add custom scripts to automatically boot after all the init.d scripts were started on old CentOS 5 and CentOS 6 versions. However, many things changed…
Read More »How can I Convert CentOS to CloudLinux OS?
Converting existing CentOS or cPanel Servers to CloudLinux isn’t hard at all and can be done within a few minutes. Today we will show you how to convert centos to cloudlinux in a few easy steps. Most cPanel installations are done using CentOS Linux, and switching from CentOS 5.x / 6.x / 7.x to CloudLinux can be done with…
Read More »Fatal error: Allowed memory size of X bytes exhausted (tried to allocate X bytes)
Fatal error: Allowed memory size of X bytes exhausted errors are one of the most common PHP errors any sysadmin will see while handling technical support requests from end users. What causes Allowed memory size of X bytes exhausted error? This happens specially when apps process large amounts of data, this happens most of the time because the…
Read More »How to Mass Change All cPanel Account Passwords
Today I found a cool way to mass change all cPanel account passwords. This simple script is really useful when you suspect most of your sites are cpanel/ftp compromised and you need to set new passwords really quickly. This tiny script will set new strong random passwords for all your cPanel users, that includes the FTP access for…
Read More »How to fix: bash: /usr/bin/curl: Permission denied
Today one of our customers was having this error while executing curl from a cron job on his cPanel website: bash: /usr/bin/curl: Permission denied The first thing to check was the curl binary, as it’s common to set it with permission 750 to disallow rouge scripts from execute curl or wget binaries. [[email protected] ~]$ ls -alh /usr/bin/curl -rwxr-x—…
Read More »How to: Hardening Linux Server TCP/IP Stack Against SYN Floods
Days ago we wrote a post called How can I Turn On TCP SYN Cookie Protection on Linux? and today we will be completing the SYN Flood solutions post series with an article focused on showing how to harden your server against SYN Flood attacks. What is a SYN Flood Attack? When an attacker tries to start a…
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