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This article was originally written for xmodulo . 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. Many applications with security features can be used to set up secure FTP services. For example, FTPS (FTP Secure) uses SSL/TLS certificates to encrypt end to end data. Based on client-side requirements, FTPS can be configured to support encrypted and/or unencrypted connections.  SFTP  (SSH File Transfer Protocol) is another method of ensuring security of transit data. SFTP is built as an extension of SSH, and can be used with other security protocols as well. This tutorial will focus on  setting up and securing FTP service using vsftpd with SSL/TLS enabled. Just a bit of background: A typical FTP server listens o...

This post was originally written for xmodulo . 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 to see the content of the transit packets with carefully placed packet sniffers. Taking the vulnerability one step further, a malicious user can even set up an impostor server in the transit path, which then pretends to be the actual destination web server. In this case, end users may actually communicate with the impostor server instead of the real destination server. This way, the malicious user can trick the end users into handing over sensitive information such as user name and passwords through carefully crafted fake forms. To deal with these kinds of vulnerabilities, most providers often prefer HTTPS in their web servers. ...

I had originally written this tutorial for xmodulo.com SSL (Secure Sockets Layer) and its descendant TLS (Transport Layer Security) are the most widely used protocols for encrypting data that is exchanged between a server and a client. These protocols often use X.509 certificates and asymmetric cryptography. STARTTTLS is another method of securing plain-text communication. This protocol also encrypts data with SSL or TLS, but with the same port as the plain-text protocols, instead of using separate ports for SSL/TLS-encrypted communications. For example, IMAP over STARTTLS uses the same port as IMAP (143), while IMAPS (IMAP over SSL) uses a separate port 993. The previous tutorial  describes how to set up a mail server running on Postfix and Dovecot, but the  security  aspect was not covered. In this tutorial, we demonstrate  how to add security to a mail server through TLS/SSL-based encryption . Certificates needed for TLS/SSL can be self-signed, signed by ...