Security

Apr 062008
 

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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 Posted by at 11:04 am
Apr 012008
 

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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 Posted by at 12:01 am
Mar 172008
 

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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 Posted by at 6:24 am
Jan 162008
 

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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 Posted by at 1:47 pm