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SSH’s (secure shell) most common authentication mode is called “interactive keyboard password authentication”, so called both because it is typically done via keyboard, and because openssh takes active measures to make sure that the password is, indeed, typed interactively by the keyboard. Sometimes, however, it is necessary to fool ssh into accepting an interactive password non-interactively. This is where sshpass comes in.

SECURITY NOTE: There is a reason openssh insists that passwords be typed interactively. Passwords are harder to store securely and to pass around securely between programs. If you

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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.

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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.

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Ptunnel is an application that allows you to reliably tunnel TCP connections to a remote host using ICMP echo request and reply packets, commonly known as ping requests and replies. At first glance, this might seem like a rather useless thing to do, but it can actually come in handy in some cases. The following example illustrates the main motivation in creating ptunnel:

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Lynis is an auditing tool which tests and gathers information from Unix based systems. The audience for this tool are security and system auditors, network specialists and system maintainers.

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Cluster SSH opens terminal windows with connections to specified hosts and an administration console. Any text typed into the administration console is replicated to all other connected and active windows. This tool is intended for, but not limited to, cluster administration where the same configuration or commands must be run on each node within the cluster. Performing these commands all at once via this tool ensures all nodes are kept in sync.

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