DenyHosts is a tool i use to secure my SSH server from these type of people. Written in python, this tool serves as a very active security guard and helps me to keep my system safe from lots of prying eyes.

There are some basic security steps that you can do to protect SSH, such as change the port from the ssh, and install a script as denyhosts.

SSH is a great way to remotely administer a server. However, it still has a number of issues when you open it up to the world. The server and client communications are secure but that doesn’t mean the hosts involved are. Opening an SSH service to the world allows for brute force attacks and means that the carbon interface is still the weakest link.

Do you think your systems are secure? Install DenyHosts and you’ll realize that you were in denial.

In this article I will show how to install and configure BlockHosts on a Debian Etch system. BlockHosts is a Python tool that observes login attempts to various services, e.g. SSH, FTP, etc., and if it finds failed login attempts again and again from the same IP address or host, it stops further login attempts from that IP address/host.

A brute force attack is an attempt to log into a secure system by making lots of attempts in the hopes of eventual success. It’s not a sophisticated type of attack, hence the name "brute force." For example, if you have a login process that requires a username and password, there is a limit as to the possible number of username/password combinations.

I created an auto install script to install Asterisk 1.2 for CentOS 4 and CentOS 5. This script will install the following:

* Zaptel
* Libpri
* Asterisk
* Asterisk Addons
* Open Source G729 Codec

Before running these script, you must install the some software needed to compile Asterisk.
For CentOS 4:

Name of some Server applications you can run in Ubuntu / Debian Linux

apache — Web server
boa — lightweight Web server
sshd — ssh server

This tutorial explains how you can install and configure APF - an interface to IPTables which lets you easily configure a full featured firewall to secure servers and workstations connected to a network. This guide describes an example installation on a server with cPanel but it's only a matter of port numbers which must be open for everything to work. APF can be used on any system.