To find additional questions and answers, and/or to ask your own questions, see the Scanner Support Forum.
It may be necessary to run the legacy version of NetworkActiv Port Scanner 4.0 for it to load correctly on Windows Server 2003 x64.
A subnet Scanner is a utility used to find computers at a given IP subnet with a given port open.
For example: To find computers with port 139 open somewhere from IP 126.96.36.199 to 188.8.131.52 one may:
Note: There are 4 small check boxes below the subnet IP box, these are to choose the scanning range, the first is to scan entire 4 sections of the IP address, the second is to scan the last 3 sections, and so on...
Common uses of a subnet Scanner are:
A Port Scanner is a utility used to find Open ports on an IP address (host), ports that are open on a system represent services, servers, and sometimes internet applications (possibly trojans), therefore a port scanner can inform you of such services, servers, etc. running on a local or remote system. Port scanning may assist you in the detection of trojans and other unwanted servers/applications, and is a great security tool.
For example: To find out if this computer is running a FTP server, one may follow these steps:
Common uses of a Port Scanner are:
What is the difference between UDP and TCP?
UDP (User Datagram Protocol) is a protocol based on connectionless comunication. UDP is ideal for things like Video Streams and Multi-Player Gaming, where a few lost packets are not a big deal, and where speed is very importent.
TCP (Transmission Control Protocol) is a protocol based on a connection between two computers. It is used for normal internet applications such as web servers, FTP servers, etc.
For TCP the timeout is to set how long the program waits for a reply on each port, if no reply within that time frame then the program declares that port to be closed.
For UDP the timeout is to set how long the program waits for a reply on each port, if no reply within that time frame then the program declares that port to be open.
The Speed setting determines the maximum number of ports per second to attemp.
If the Speed is set too high for TCP then the scanner may use too much resources, and may miss some or all ports that are open.
If the speed is set too high for UDP then the scanner will find ports that are not really open.
On the left side of the application, there is a start and stop port field, also, there is an IP/address field. These fields are for the port scanners and other host based operations such as ping.
On the right side of the application, there is an IP address field along with a port field. These are strictly for the subnet scanners and ping scanner.
The keys to ensuring high performance are:
The Read timeouts are to set how long the program waits for data reply after connecting to a port.
For port scanning this setting determines how many extra packets to send uppon finding a possible open UDP port.
For subnet scanning this setting determines how many extra packets to send uppon finding a valid computer (UDP w/port only).
The purpose of this setting is to lower the chance of finding UDP ports to be open when they really are closed.
Ping scanning is a scanning technique used to find IP's (hosts) that are currently up (connected) on a given IP subnet.
Paste the address/IP into the port scanning address box, then simply click the small arrow directly to the right of the port scan address box.
UDP ping mode vs standard (ICMP ping mode) mode: The difference is simply that UDP ping mode sends UDP packets to port zero on the host being scanned (port zero can never be listening, and will therefor reply), and standard ping mode sends standard ICMP echo request packets to the host being scanned.
NetworkActiv Scanner 4.0 current known bugs/issues:
There are currently no known bugs or issues.
NetworkActiv Scanner V3.0 current known bugs/issues:
Note: These bugs have been fixed in the next release (Use button in About of program to occasionally check for newer versions).
In the case that you find a bug and/or issue in NetworkActiv Scanner that is not mentioned above please send us an email explaining the situation, your operating system, and the version of NetworkActiv Scanner you are using.
When the SYN wait for reply check option is checked the scanner will not send more than the Max Stray packets without having received them back, if packets are lost during the scan this option will cause the SYN scan system to slow down and stop sending packets.
If this problem occurs it is recomended to uncheck the SYN wait for reply option and scan again.
When checked, the scanner will only scan ports that are in the port range specified and are in the internal port list (a list of common ports). Basically, if you were to enter from port 1 to 65535 for the range, the scanner would check all known ports. This type of scan will be faster because time is not wasted on the checking of un-common ports.