Port scanning is the act of systematically scanning a computer’s ports. A port on a computer is a place where information goes into and out of the computer and port scanning identifies the status of any of these ports.
Port scanning has legitimate use in network management but it can also be used in a malicious nature if an attacker is looking for weakened access point to break into a computer. Usually services running on these ports broadcast version and other information about itself for troubleshooting and other kinds of uses but this also gives a lot of information to the would be attacker.
Type of port scans
This type of scan attempts to connect to all known 65,535 ports
This is a more focused scan and looks for only known services to exploit
This type of scan sends packet fragments that get through simple packet filters in a firewall and later joined back together at the target
This type of scan looks for all open UDP ports
This kind of scan connects on the same port on more than one machine for example looking for any FTP servers an attacker would do a sweep scan for port 21 over a range of given network machines
This kind of scan prevents the scanned computer from recording the port scan activities, this is due to the structure of the request sent by the port scanner.
Tools of the trade
The most popular tool for port scanning is nmap and provides a wide variety of options of performing different kind of port scans like stealth scans and many more. Its modular architecture has also enabled development of plugins that have expanded its capabilities
These attacks can now be easily detected by firewalls and intrusion detection systems. Current intrusion detection systems like snort can at times frustrate the attacker by dropping packets used in scanning giving the port scanning tools false positives.
Some other way of defeating the port scans is to install services on ports other than the default ports and also to disable display of service banner information to stop any finger print scans
Port scanning is not illegal per se but is most times indicative of beginnings of an attack hence measure have to be taken to secure any internet facing devices.
What is CMD?,
Basically CMD stands for Command, CMD is the interface which was used in the early ages of the computer revolution before a Graphical User Interface was invented by Apple .Inc on a Macintosh Computer. The graphical User Interface was later adopted by the PC or Windows computer later on. The CMD interface or window is normally a black screen with lines and it operates with commands issued by the user through keyboard input.
To launch the command line on a windows 7 or later version, Press the Windows Key, Type “CMD”, (without the quotes) and hit the return or Enter key on the Keyboard.
A window like the one below will be launched and you will be able to proceed with checking for system software and hardware specification.
To check for system software and hardware, Type “systeminfo” in the command line and press the Enter on your keyboard.
If you are tin-foil hat wearing person who looked at the acquisition of whatsapp by facebook with disdain and anger and wondered how easy or hard it is to setup your own chat service then I have just what the doctor ordered. Before you embark on your journey of rebellion you have to be warned of the perils of high technology and pits of despair while testing but stand firm pilgrim.
First off you need to understand what protocols the chat services use, whatsapp uses highly modified versions of xmpp both on the server side and for handling things like authentication…but will try to keep this not too technical.
If you receive warnings that your virtual memory is low, you'll need to increase the minimum size of your paging file. Windows sets the initial minimum size of the paging file equal to the amount of random access memory (RAM) installed on your computer plus 300 megabytes (MB), and the maximum size equal to three times the amount of RAM installed on your computer. If you see warnings at these recommended levels, then increase the minimum and maximum sizes.
1. Open My Computer
Note: The elevated commandline is an administrative terminal for the windows OS, therefore be careful with the commands as they can crash your computer and fail to boot again which may lead to loss of data.
Press windows key
Type “cmd” without the quotes
Press and hold down Ctrl + Shift + Enter on the keyboard.
You will be prompted to accept launching of the elevated commandline, select YES.
To adjust date from the elevated commandline, type “date”, without quotes, and enter the date in the format month-day-year (mm-dd-yy)
Hit the return key after entering the correct date.