System Shut Down
shutdown -h now (Displays the file hello.txt)
shutdown -h +15 (Displays the file hello.txt)
shutdown -r now (Shut Down > Restart now)
shutdown -r +15 (Shut Down > Restart in 15 minutes)
IP Configuration (Edit the ifcfg-eth0 file):
cat /etc/sysconfig/network-scripts/ifcfg-eth0 View the configuration file for eth0
vi /etc/sysconfig/network-scripts/ifcfg-eth0 Edit and Save the configuration file for eth0 Read more…
A video from The Linux Foundation, commemorating 20 Years of the Linux Operating System: Read more…
DNS servers can be attacked using various techniques including:
- DNS spoofing
- Cache poisoning
- Registration hijacking
One of the simplest ways to defend is to strictly limit zone transfers between nameservers by defining an ACL. Many system administrators allows BIND to transfer zones in bulk outside of their network or organisation. This is an attack vector. You can prevent this by using ACLs: Read more…
named.conf
Create /etc/named.conf file specify the directory location of other files used by DNS: Read more…
A Record
The majority of DNS records are “A” records. A records allow for you to point different sections of your domain to different IP addresses or servers. For example, this would be useful for having “www.domain.com” point to your web server’s IP address and “mail.domain.com” point to your mail server’s IP address. Each record includes a “Host Name” value and a corresponding IP Address. Read more…
This is a link to a brief description of what happens in a Linux system, from the time that you turn on the power, to the time that you log in and get a bash prompt. Understanding this will be helpful when you need to solve problems or configure your system.
http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html
Greg O’Keefe, gcokeefe@postoffice.utas.edu.au
Both the ~/.bashrc and ~/.bash_profile are scripts that might be executed when bash is invoked. The ~/.bashrc file gets executed when you run bash using an interactive shell that is not a login shell. The ~/.bash_profile only gets executed during a login shell. What does this all mean? Read more…
These YouTube Videos show how simple it is to create Virtualized and Para-Virtualised Guest Operating Systems using Xen Hypervisor Read more…
Matching TCP traffic with particular flag combinations can be a useful way of examining TCP conversations. Refer to the TCP State Machine to understand the context of these flags: Read more…
