How to use the command line to list password files on a Macintosh machine.

This is how to list the password files on a Macintosh OSX Mountain Lion machine. Newer Macintosh OSX machines do not use the /etc/shadow file link Linux does, so this is how the account passwords are stored. Homers-iMac:~ homer$ sudo ls -lah /var/db/dslocal/nodes/Default/users/ Password: total 336 drwx—— 74 root wheel 2.5K 14 Mar 10:13 . […]

How to list the password files on a Macintosh OSX Lion computer.

This is how to list the password files on a Macintosh machine, but the folder is only readable by the superuser. Admins-iMac-203:~ admin$ ls -lah /var/db/dslocal/nodes/Default/users/ ls: /var/db/dslocal/nodes/Default/users/: Permission denied I was unable to view this content as I was unable to get root permissions on the Macintosh machine I was using today. I am […]

Simple MikroTik routing. Some useful links and information.

Simple static routing with a Mikrotik device. These links are useful when you are setting up a Mikrotik device and you need assistance with the complex setup of one of these tiny but powerful devices. Creating a DMZ with a Mikrotik device. Simple firewall script for a Mikrotik router. Mikrotik Wireless FAQ. […]

Windows XP support ending soon, this will mean that security holes in existing installations will be exploited.

The support for Windows XP will end soon. April 8th in fact. This means that existing installations of Windows XP, and there are many around the world will be rendered vulnerable to exploits. Windows XP has been around since 2001 and it is time that is was replaced by something better. Windows 7 is still […]

Networking terms and their meanings.

Some common networking terms and their meanings. IPv4 – IP version 4: This is the current networking standard that defines an IP address with a 32-bit address composed of four octects. IPv6 – IP version 6: A newer standard of IP addressing that will replace the current IPv4. This uses a newer and more efficient […]

How to save your iptables firewall rules using the iptables-persistent package for Linux.

The iptables firewall is the built-in firewall for protecting a Linux machine from online threats. But the settings are not save upon a re-boot. This is easily alleiviated by installing the iptables-persistent package for Ubuntu. Once this is installed, you will be greeted with a screen that will ask you if you wish to save […]

How to use the ping command in a script to get an IP address automatically and ping it.

This command will get the IP address from the interface supplied and then ping it. ping $(ifconfig enp6s1 | awk ‘/inet / { print $2 } ‘ | sed -e s/addr://) Here is an example. This shows how well this works. [homer@localhost ~]$ ping $(ifconfig enp6s1 | awk ‘/inet / { print $2 } ‘ […]

Mt Gox source code leaked to the Internet. This is a good example of how not to setup a bitcoin exchange.

This is a screenshot of some leaked source code for a Bitcoin exchange. This source code is intended to access a MySQL database. Here is the full code listing: The bitcoin digital currency was devised to allow payment over the Internet using a digital currency. This breach shows that security is not absolute. But […]

Some more beautiful wallpapers for your high-resolution Linux desktop. Crater lake wallpaper. This one is very nice indeed. Full moon over a Greek township. Illuminated Alhambra, Andalusia (Spain). Kuala Lumpur at night. Quiraing, Isle of Skye (Scotland, U.K.). Windmills, Kinderdijk (Netherlands).×1080/17/outer_space_stars_planets_rings_digital_art_1920x1080_16429.jpg. A massive crater on a moon and Saturn in the background. Awesome HD space wallpaper.×1080/63/digital_art_outer_space_sea_1920x1080_62719.jpg. […]

The Importance of Good IT management for Small Business.

Enterprise computing may seem like something that only belongs deep in the halls of a large business. The reality is that it is something that should be considered by every business. If a company has more than a single computer at work for them, then networking technologies should be in place. Anytime a business connects […]

Strange but useful shell trick with the bash shell.

This is a very strange shell trick that allows you to have a set of parameters to a Linux command that are separated by single quotes. [homer@localhost ~]$ df -h’l’a’T’ Filesystem Type Size Used Avail Use% Mounted on rootfs rootfs 216G 75G 130G 37% / proc proc 0 0 0 – /proc sysfs sysfs 0 […]

Useful networking study resources for students.

Some useful networking resources. TCP and UDP reference. TCP/IP Ports listing. This is very useful for reference. Another TCP ports listing in HTML. An introduction to the OSI model and how the TCP/IPĀ  Protocol works. A definition of common TCP/IP names. Intro to TCP/IP. TCP/IP and subnet masking explained. Kali […]

How to list all iptables rules that are set on your Linux system. This is very easy.

The iptables -L or iptables –list commands will list all of the iptables rules that are set on your Linux machine. Below is abbreviated output of this command on my Fedora 20 system. [root@localhost homer]# iptables –list Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT all — anywhere anywhere ctstate RELATED,ESTABLISHED ACCEPT all […]

Another very useful BIOS simulator. This is for a Phoenix BIOS. This is a BIOS simulator that allows a visitor to practice using a Phoenix BIOS in a web browser. This is a very useful page for playing around with BIOS settings without hurting anything. There is another simulator here: Thinkpad X40 BIOS simulator. This one is also very interesting to play with. More BIOS […]

How to find a file with Linux using the command line.

The Linux command line offers useful tools that enable you to find files easily. The find command is one useful example. Here I am using the find command to look for all *.png files in a folder. homer@deusexmachina ~/Documents $ find /usr/share/backgrounds -name “*.png” /usr/share/backgrounds/linuxmint-petra/linux_mint_16.png /usr/share/backgrounds/linuxmint-petra/petra.png /usr/share/backgrounds/warty-final-ubuntu.png And using wildcards to find all files with […]