A recent vulnerability was found in the OpenSSL package as provided by Debian and Debian-based Linux distributions, such as Ubuntu, that broke the effectiveness of the OpenSSL PRNG (Predictable Random Number Generator). This vulnerability caused OpenSSL to generate weak keys for anything relying on OpenSSL, including SSL certificates, OpenSSH keys, and OpenVPN keys.
Security
We have already dicussed how to install and configure postfix now we will learn about How to add a Disclaimer To Outgoing Emails in Postfix using altermime.
alterMIME is a small program which is used to alter your mime-encoded mailpacks as typically received by Inflex, Xamime and AMaViS.
If you forget your password for compressed archive (rar, 7z, zip), this program is the solution.This program uses bruteforce algorithm to find correct password. You can specify wich characters will be used in password generations.
We have already discussed how to install mail server with postfix+Devcot+SASL+Squirrel Mail in this article we will see how to add spam filter for postfix mail server.
Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache SpamAssassin to be used in a wide variety of email systems.
autossh is a program to start an instance of ssh and monitor it, restarting it as necessary should it die or stop passing traffic. The idea is from rstunnel (Reliable SSH Tunnel), but implemented in C. Connection monitoring is done using a loop of port forwardings. It backs off on the rate of connection attempts when experiencing rapid failures such as connection refused.
