I have started to use .local dns extension for my local network. After changing my complete network configuration I realized that some of my Ubuntu machines can resolve the FQDNs ending with .local (Ex: testhost.digitalpains.local ) correctly. ali@advance17:/home/ali$ ping testhost.digitalpains.local ping: unknown host testhost.digitalpains.local   ali@advance17:/home/ali$ ping testhost PING testhost.feasiblesolutions.local (192.168.7.2) 56(84) bytes of data. [...]

Responding to a ping request can not be the part of job definition for a production/critical server. For critical systems It is better not to publish information more than it is absolutely necessary. Disabling response to ICMP ECHO requests is a measure we can easily implement. Tweet This Post

There are two possible ways for adding a default gateway. Option 1: You can add a gateway definition to  the /etc/sysconfig/network file. This definition will apply to all network interfaces. Let’s say that your gateway is 192.168.4.1,  then you need to add the following line to /etc/sysconfig/network file. GATEWAY=192.168.4.1 Option 2: You can define a [...]

Ubuntu 9.10 installation by default enables the IPv6 and if you are having performance problems with Firefox it is quite likely that it can be solved by disabling IPv6. You can disable IPv6 at Firefox level or kernel level. For the necessary step here is a nice article you can follow. Tweet This Post

At our previous article ”Installing Ubuntu KVM Virtualization Host” we have installed a Virtualization Host. Actually standard installation already made some network configurations for us. As you can see below our virtualization host has a bridge network virbr0. This bridge network will be used by our virtual machines and they will receive an IP number from [...]

If you want to access the services on your KVM machines from Internet, it is most likely that you would need a bridge network interface. Let’s see how you can define a bridge network on Ubuntu. Tweet This Post

What kind of protection do you have at your home or small office network? Are you using iptables? windows firewall or firewall of your adsl modem? Now a days having just a firewall is not good enough for your protection. Actually you can also see this from the way open source firewall projects are evolving. [...]

I am working on a KVM based virtualized environment.  All my virtual machines are sitting behind a virtual firewall appliance. Here comes the challenge. I need to identify and open up required ports for each individual appliance. What are the ports a mailserver would need? Here is the list of ports you need to open [...]