SPF is an e-mail anti-forgery technology the enables domain owners to list, in the Domain Name Service (DNS), authorized sources of mail from their domains. It enables mail receivers to reject mail that does not come from authorized sources. This…
amavisd-new is a high-performance interface between mailer (MTA) and content checkers: virus scanners, and/or SpamAssassin. It is written in Perl for maintainability, without paying a significant price for speed. It talks to MTA via (E)SMTP or LMTP, or by using…
OpenDMARC is an open source implementation of the Domain-based Message Authentication, Reporting and Conformance (DMARC) specification. DMARC is a policy for mail transfer, which is already supported by some common mail providers. It depends on Sender Policy Framework and DKIM.…
Postgrey is a Postfix policy server implementing greylisting. When a request for delivery of a mail is received by Postfix via SMTP, the triplet CLIENT_IP / SENDER / RECIPIENT is built. If it is the first time that this triplet…
Puppet is the most powerful configuration management tool in the solar system. It’s the engine that drives your compliance, baseline, drift remediation, and deployment needs. It has always been and always will be open source, with freely downloadable operating system-specific…
MariaDB Server is one of the most popular open source relational databases. It’s made by the original developers of MySQL and guaranteed to stay open source. It is part of most cloud offerings and the default in most Linux distributions.…
Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. It reduces bandwidth and improves response times by caching and reusing frequently-requested web pages. Squid has extensive access controls and makes a great server accelerator. It…
The purpose of unattended-upgrades is to keep the computer current with the latest security (and other) updates automatically. If you plan to use it, you should have some means to monitor your systems, such as installing the apt-listchanges package and…
A caching proxy. Specialized for package files from Linux distributors, primarily for Debian (and Debian based) distributions but not limited to those.
Fail2ban scans log files and bans IPs that show the malicious signs — too many password failures, seeking for exploits, etc. Generally Fail2Ban is then used to update firewall rules to reject the IP addresses for a specified amount of…