Category: Guides
08/12/06
Network Time Protocol Daemon
The NTP is designed to keep clocks on multiple servers synchronized to Atomic Time and is a great tool for Server Administrators. You may be asking why a tool like this is important or why it would be necessary. Well the answer is very simple; over time, time keeping devices tend to "drift" off of an accurate measure. For instance, the watch on your wrist will drift over time and this is still a problem that occurs even on the most modern computers.
Prerequisites
- The examples in this article are all shown on FreeBSD 6.x
- The NTPd is part of the FreeBSD base files. You can install the daemon from ports but that is not covered in this document
- A CLI editor such as ee
- Additional files and references may be found at the end of the article
Read more!05/02/06
DenyHosts
A bruteforce attack is an attempt at getting past a login request by repeatedly entering combinations of words, letters, and numbers found in a dictionary file created by the attacker. Blocking these attacks may seem unnecessary for a system administrator with a complex password; however, putting a stop to them not only keeps your system more secure but it will save bandwidth in the long run and also cut down on those lengthy login failed security e-mails.
DenyHosts is a wonderful tool for blocking these bruteforce attacks on your SSH daemon. It works by scanning through your authlog, finding the IPs that constantly try to enter your server and fail, and then denying them SSH access to the server.
03/01/06
eAccelerator
eAccelerator is a PHP cacher. It is the continuation of a really popular project known as Turck MMCache. Like its predecessor, eaccelerator is both free to the public and open source. Unlike its predecessor, it has support for PHP 5.x.
eAccelerator's main function is to cache PHP scripts in a precompiled state. Normally when you write PHP scripts for your website the source code is not compiled. The compilation is done on access. On every access. eAccelerator takes your source code and stores it compiled in Shared Memory as well as on your hard drive. This completely eliminates the need to compile every time on every access. Naturally, this is a very good idea for Server Administrators to apply to their PHP enabled servers.
Before we begin, we need to check a couple of prerequisites. First, you CAN NOT use a PHP cacher if you have PHP compiled as a CGI binary. Second, check to see if you have a Zend Loader installed. If you don't know what that is then don't worry because you probably don't have one. Last but not least, if you have ionCube installed then you will need to unload it from your php.ini file and use runtime-loading.
