Category Archives: Tips and Tricks

Email FreeBSD Security Tips and Tricks

Identifying malicious mail scripts on FreeBSD

This article will help you identify an possible spam scripts that may be causing unwanted outbound mail which could cause your servers ip address to be blacklisted.There are many different ways a script may get onto the server however we I will provide several different tools and methods to help identify scripts.   PHP scripts …

Administration CentOS Fedora FreeBSD Linux Tips and Tricks

Identify the process that is using some specific port

Sometimes, you may encounter a situation where you see some ports being used by some service, but you cannot exactly determine which application/service is using it. This article talks about how to identifying such services. FreeBSD In the case of FreeBSD, you can use “lsof” command to determine the service that is reserving port as below. lsof -i :199 …

Administration FreeBSD Linux Tips and Tricks

Some useful ‘find’ commands

The ‘find’ command is quite useful as it helps to identify files with specific permissions, users,groups, size, etc.  Also, it is quite helpful to as it allows to process its results when combined with other commands. This article talks about some useful ‘find’ commands. Find all files named ‘test.jpg’ inside /home directory             …

CentOS Debian Fedora FreeBSD Linux Tips and Tricks Ubuntu

A Basic Overview of the Vim Text Editor

Many articles in our Webair Community advise editing configuration files. We usually recommend using your preferred text editor. I personally prefer vim. Vim, or its older sibling vi, are installed by default on nearly every server that I come across. If you do not yet have a preferred text editor, read on to see if …

Administration CentOS Debian Fedora Linux Tips and Tricks Ubuntu

How to Manage a Linux Server with systemd

What Operating Systems Have Adopted systemd? CentOS: Yes, by default since CentOS 7 Fedora: Yes, since the release of Fedora 15 RedHat: Yes Debian: Yes, shipped since Debian 7 as a technology preview Arch: Yes Ubuntu: Available Gentoo: Available OpenSUSE: Available Slackware: No   What About chkconfig and Other Legacy Commands? With systemd it is …

Administration Apache Security Tips and Tricks

Prevent hot linking of images.

Hot linking is displaying an image on a website by linking to the same image on another website, rather than saving a copy of it on the website on which the image will be shown. Lets say, you have an image at www.yourdomain.com/image.jpg and it is not well protected. If someone links this image to …

Administration FreeBSD Linux Tips and Tricks

Setting files as immutable.

Wouldn’t it be nice if we can set files so that even root cannot modify or delete it ? Both FreeBSD and Linux come with commands that allows us to set files as immutable. If you have files that you don’t want anyone to modify/delete by mistake, then these commands are quite useful.   FreeBSD …

Security Tips and Tricks

How to Create a Self-Signed SSL Certificate

An SSL certificate is ideal for securing an administration interface, a member’s-only space, an intranet, webmail. etc. It is used is to keep sensitive information sent across the Internet encrypted so that only the intended recipient can understand it. When installed on a web server, it activates the padlock and the https protocol (over port …