dreamsys software



Network Port Scanner Help





Network Port Scanner is an advanced network utility for finding ports that are open on any machine or range of machines on a network. Finding open ports on a host can be one of many things. An open port can be a server service like FTP or HTTP that a user on the node may or may not be allowed to run under the network's administration rules. An open port may also be a backdoor trojan program that a hacker installed through a virus or remote administration exploit.
It is very important to find these holes in your network because any machine that can be compromised on your network brings a hacker one step closer to having full administrative privlidges on your network, and ultimately destroying important data, or even spying on sensitive data.

To setup your port scanner you will need to basic forms of input. A host IP address (or a range of IP addresses), and a port (or a range of ports). Let's say you have 3 networks that you want to scan (10.1.1.0, 10.1.5.0, and 10.1.10.0), on all 3 networks, you want to make sure that none of your users are running FTP or HTTP servers, you also want to make sure that they have Telnet disabled so that a hacker may not try to login to thier machine.

First click the "Edit" button next to the host list (or Hosts->Edit from the menu). This will bring up the list of hosts you will be scanning. Click the "Add Range" button to add your first network. This will bring up the Add Range Dialog. In the "Start Address" field, enter the value 10.1.1.1, and in the "End Address" field, enter 10.1.1.255. Click the OK button. This will add the whole range of IP addresses to your scan. Repeat these steps for the next 2 networks. Click the OK button when finished adding ranges of hosts to scan.
Now that you have your hosts added to your scan, it is a good idea to save them to a host list file if you may want to scan these same ranges on a regular basis. Select "Save" from the "Hosts" menu. This will bring up the File Save dialog box, name your file, and any time in the future you may select the menu item Hosts->Load to reload your host list.



The next step will be to add your range of ports you want to scan. Click the "Edit" button next to the port list (or Ports->Edit from the menu). This will bring up the list of ports that you will be scanning for on your hosts. There are 3 ports that you want to scan for, FTP (21), HTTP (80), and Telnet (23), so click the "Add" button, and enter 21 for your first port and click OK. Repeat these steps for port 80 and 23, then click OK when you are finished adding ports to your scan.
Now that you have your ports added to your scan, it is a good idea to save them to a port list file if you may want to scan these same ranges on a regular basis. Select "Save" from the "Ports" menu. This will bring up the File Save dialog box, name your file, and any time in the future you may select the menu item Ports->Load to reload your host list.



Now that you have your hosts and your ports, you are ready to start your scan. To start your scan click the "Scan" button, or Scanner->Scan from the menu. When the port scanner finds an open port, it will add it to the results list. If you double click the entry in the results it will invoke the application associated with that port (for more info see the "Common Ports Dialog" description below). You can save and load your results just like you can with the hosts and ports lists.



Common Ports Dialog
If you do not know the port number for the service that you are looking for, you may browse the list, by selecting "Ports->View Common Ports" from the menu. This will bring you up the Common Port Editor Dialog. From this dialog, you can view, add, edit, or remove ports from the common ports list. You can edit the description, and the way that the port scanner will behave when a found port is double clicked. When the user double clicks a found port, the port scanner will launch the associated application with the given command line. Anywhere there is a %a in the command line, it will subsitute the IP address, and anywhere there is a %p, it will substitute the port. For any port that doesn't have sepecific application info given, it will launch the default "Telnet" with the command line "%a %p".



Port Scanner Options
To increase the speed of your scan, you can edit the scan options by selecting the menu item Scanner->Options. This will bring up the Scanner Options Dialog. In this dialog, you can set the timeout variable (2000 by default) and the maximum number of threads for the scan. It is not recommended to use more than 20 threads because this will cause the connections to drop easier and may not show you all of the data you would get by using less threads. If you are scanning a local network, it's a good idea to set the timeout variable much lower to increase the speed of your scans. If your average connection time to a host is under 100 milliseconds, set the timeout to 100. This will greatly increase the speed of your scan.


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