How to set up two-factor authentication for SSH login on Linux

With many high-profile password leaks nowadays, there is a lot of buzz in the industry on “multi-factor” authentication. In a multi-factor authentication system, users are required to go through two distinct authentication procedures: providing something they know (e.g., username/password), and leveraging something they have “physical” access to (e.g., one-time passcode generated by their mobile phone). […]
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How to set up a secure FTP service with vsftpd on Linux

FTP or File Transfer Protocol is one of the widely used services on the Internet, mainly for transferring files from one host to other. FTP itself was not designed as a secure protocol, and as such, the classic FTP service is vulnerable to common attacks such as man in the middle and brute force attacks. […]
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How to set up Samba as a Primary Domain Controller

A domain controller is a server which groups multiple computers to centralize their authentication system. When you are using a domain controller, you don’t login to your computer, but instead login to the domain controller. Every authentication request is handled by the Primary Domain Controller (PDC). Usually you hear about PDC using a Windows based […]
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How to manage passwords from the command line on Linux

With password-based authentication so prevalent online these days, you may need or already use some sort of password management tool to keep track of all the passwords you are using. There are various online or offline services or software tools for that matter, and they vary in terms of their sophistication, user interface or target […]
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How to set up a transparent HTTPS filtering proxy on CentOS

HTTPS protocol is used more and more in today’s web. While this may be good for privacy, it leaves modern network administrator without any means to prevent questionable or adult contents from entering his/her network. Previously it was assumed that this problem does not have a decent solution. Our how-to guide will try to prove […]
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How to set up HTTPS in Apache web Server on CentOS

Web servers use HTTP by default, which is a clear text protocol. As the name suggests, a clear text protocol does not apply any form of encryption on the transit data. While the HTTP-based web server is very easy to set up, it has a major drawback in terms of security. Any “man-in-the-middle” is able […]
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How to set up MailScanner, Clam Antivirus and SpamAssassin in CentOS mail server

In the world of mail servers, MailScanner is one of the best open source software for virus scanning and spam detection. MailScanner relies on pre-installed anti-virus and anti-spam software to check incoming and outgoing emails for malicious content or patterns of spamming. This makes sure that the mail server does not participate in the distribution […]
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How to set up Clam Antivirus, SpamAssassin and MailScanner on Ubuntu mail server

Antivirus and anti-spam protection are the among the most important security features for a mail server. Unix/Linux based mail servers are typically invulnerable to malware and viruses, and there is a very slim chance that the server itself may get infected. On the other hand, the operating system of an end user device may not […]
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How to enable user authentication for a Postfix SMTP server with SASL

Every mail server administrator dreads his or her server becoming compromised by spammers. A lot of effort, time and even money is spent on securing mail servers and making sure that the servers do not become open relay. To combat against spambots in an SMTP server, Postfix in general uses the mynetworks parameter to specify […]
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