On Red Hat based Linux, iptables comes with certain default rules. It is good idea to clean them up, and start from scratch. This article is part of an ongoing iptables tutorial series. This is the 2nd article in that series. In our 1st part, we discussed about IPTables Tables, Chains, Rules Fundamentals. Before we [...]
January 2011
Rsync is very powerful tool to take backups, or sync files and directories between two different locations (or servers). You know this already, as we presented you with practical examples on rsync earlier. In a typical backup situation, you might want to exclude one or more files (or directories) from the backup. You might also [...]
iptables firewall is used to manage packet filtering and NAT rules. IPTables comes with all Linux distributions. Understanding how to setup and configure iptables will help you manage your Linux firewall effectively. iptables tool is used to manage the Linux firewall rules. At a first look, iptables might look complex (or even confusing). But, once [...]
Expect scripting language is easy to learn. It expects specific string, and sends (or responds) strings accordingly. If you are new to expect, read our 6 expect script examples (including hello world example) to get a jump start. This article explains the following in the expect scripting language. Expressions – arithmetic operation if construct in [...]
In our previous regular expression part 1 article, we reviewed basic reg-ex with practical examples. But we can do much more with the regular expressions. You can often accomplish complex tasks with a single regular expression instead of writing several lines of codes. When applying a regex to a string, the regex engine will start [...]
To run various open source applications you might have to install Apache, MySQL, PHP, and Perl (or some combination of these). For those who have difficulties installing and configuring these separately, XAMPP might be helpful. XAMPP is Apache distribution that contains MySQL, PHP and Perl. You really don’t need to worry about configuring MySQL, PHP, [...]
Question: How do I check whether my HP Unix operating system HP-UX is running on 32-bit or 64-bit? Answer: If you’ve installed it, you should know, as the installation CD (or ISO image) for a 32-bit HP-UX and 64-bit HP-UX are different. Let us assume that your sysadmin installed the OS, and you didn’t know [...]
Here is the good, bad and ugly scenario for backups. Ugly – Not having a backup. When the application or database crashes, you are screwed. Bad – Taking regular backup, but storing the backup on the same server. When the application or database crashes, you can restore it from the backup located on the same [...]