Apr 302012
 

Varnish is an open source “web accelerator” which you can use to speed up your website.

It can cache certain static elements, such as images or javascript but you can also use it for other purposes such as Load balancing or some additional security, in general most of the people want to try it and test their website to see if it’s really so amazing (IMO yes, but test it yourself).

The traditional guides will tell you to move your webserver to another port, perhaps 81,8080 or just bind to localhost, configure Varnish to listen to port 80 and use the web server as backend, the server where Varnish will forward requests not found in his cache.

This is the “normal” configuration and it works fine, but sometimes you just want to make a quick Test or perhaps you are using a Control Panel, such as Cpanel, Kloxo or ISPConfig and in my experience change the standard listening ports of Apache is not a decision to be taken lightly with these tools.

So in a VPS (with Kloxo) I’ve used a different approach: iptables.
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Nov 012011
 

sshguardI’ve already talked about fail2ban and logcheck, 2 tools that can scan your logs and do actions, based on rules that you can give/modify, usually modify your iptables rules to stop active attacks against your server or simply send you a warning if some thing is found in the logs.

Today we’ll see a similar tool, sshguard, it is different from the other two in that it is written in C, so it’s uses less memory and CPU while running, but still achiving the same results.
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Online resource collection for Linux Administrators

These are some sites i use to do specific jobs, i hope they can serve you well too. Corntab Corntab is a simple crontab web GUI With Corntab you can ensure that you always have the correct crontab syntax. Don’t worry about forgetting the proper crontab format because Corntab let’s you click on all of [...]

ufw – Iptables under Ubuntu

I use iptables by many years and used it also for complex solutions and only recently i’ve discovered ufw (Uncomplicated Firewall), the ubuntu version, or better developed to ease iptables firewall configuration, ufw provides a user friendly way to create an IPv4 or IPv6 host-based firewall. By default UFW is disabled.