Q. How do I detect port scan attacks by analyzing Debian Linux firewall log files and block port scans in real time? How do I detect suspicious network traffic under Linux?
A. A port scanner (such as nmap) is a piece of software designed to search a network host for open ports. Cracker can use nmap to scan your network before starting attack. You can always see scan patterns by visiting /var/log/messages. But, I recommend the automated tool called psad – the port scan attack detector under Linux which is a collection of lightweight system daemons that run on Linux machines and analyze iptables log messages to detect port scans and other suspicious traffic.
psad makes use of Netfilter log messages to detect, alert, and (optionally) block port scans and other suspect traffic. For tcp scans psad analyzes tcp flags to determine the scan type (syn, fin, xmas, etc.) and corresponding command line options that could be supplied to nmap to generate such a scan. In addition, psad makes use of many tcp, udp, and icmp signatures contained within the Snort intrusion detection system.
Install psad under Debian / Ubuntu Linux
Type the following command to install psad, enter: $ sudo apt-get update $ sudo apt-get install psad
Quand votre nom de domaine pointe vers un hébergement mutualisé, vous n’avez, la plupart du temps, pas le droit de modifier les VirtualHost du serveur Apache.
Virtual Hosts
Pour pallier ce manque, une redirection s’impose mais par un autre biais: l’utilisation de l’URL Rewrting. Lire la suite…
VirtualBox 4.0 got a very cool new feature that allows you to easily resize a hard disk in just a few seconds. Previously, you had to install Gparted to do this and the procedure was quite slow.
In VirtualBox 4.0+ (see how to install VirtualBox 4.0.x in Ubuntu), to resize a VirtualBox hard disk image (.VDI) firstly locate the folder where the .vdi you want to resize is located – this should be under ~/VirtualBox VMs or ~/.VirtualBox/HardDisks. Then open a terminal, navigate to that folder (« cd /FOLDER/PATH ») and run the following command to resize the .VDI:
Where YOUR_HARD_DISK.vdi is the VirtualBox hard disk you want to resize and SIZE_IN_MB is the new virtual hard disk size, in megabytes. For example, the following command will resize the VirtualBox hard disk called « natty.vdi » to 12000 megabytes:
VBoxManage modifyhd natty.vdi --resize 12000
That’s it! The process takes just a few seconds and you should now have a resized VirtualBox hard disk.
