Archive for May, 2011

Example IPTables rules for a webserver

Just a quick and basic example IPTables ruleset to secure a web/mail server: # Allow outgoing traffic and disallow any passthroughs iptables -P INPUT DROP iptables -P OUTPUT ACCEPT iptables -P FORWARD DROP # Allow traffic already established to continue iptables -A INPUT -m state –state ESTABLISHED,RELATED -j ACCEPT

Don’t be a Tw@t – Use At!

Sigh today I made a schoolboy error – making config changes to a live firewall on a remote server without giving myself any kind of safety net! Anyway, this is an example of where you should really use something like the at command to bail you out should anything go wrong: get the current system […]

Android Apps for a System Administrator

With phones getting smarter and smarter, its now possible to monitor servers and perform basic administration tasks from your android handset. Here are a few tools I find useful. Connectbot is a great SSH client for the Android. It is fully functional, supporting SSH keys and copy/paste etc.   For Windows RDP connections, I found […]

Screen – Can be useful!

Screen is something I’ve never been interested in using previously, but to be honest, it has many benefits. Screen is basically a window manager that allows you to run many windows from your SSH session. By doing this you don’t need to initiate several SSH sessions to a box when running complex tasks. Also if […]

Install Java 1.6 JRE and JDK On CentOS5

Very busy right now, so here’s a quick and dirty writeup for install Java 1.6 on centos5. To install the JDK yum install -y jpackage-utils wget http://cds.sun.com/is-bin/INTERSHOP.enfinity/WFS/CDS-CDS_Developer-Site/en_US/-/USD/VerifyItem-Start/jdk-6u14-linux-x64-rpm.bin?BundledLineItemUUID=KxWJ_hCuwSUAAAEvTWRZB8TT&OrderID=WeuJ_hCuedUAAAEvLGRZB8TT&ProductID=tPxIBe.oz2IAAAEhmh0zLjfT&FileName=/jdk-6u14-linux-x64-rpm.bin chmod +x jdk-6u14-linux-i586-rpm.bin ./jdk-6u14-linux-i586-rpm.bin