Active ports scanner and NetTools

Active Ports  (download)
active-ports.software.informer.com/1.4/
Active Ports is a tool that monitors all open TCP and UDP ports on a local computer.
You can watch which process has opened which port, because the program maps ports to its owning application.
Active Ports 1.4 also displays a local and remote IP address for each connection and allows you to terminate the owning process. In this way, this program can help you to detect and stop trojans and other malicious programs.
When you run Active Ports 1.4, it scans all your open ports, and displays the following information about them: Process Name, PID, Local IP, Local Port, Remote IP, Remote Port, State, Protocol and Path.
If you want to know more about certain process, you can click on it and press the "Query Names" button. You will then see the name of the server trying to reach your IP.
If you don´t trust that process, you can terminate it through this program, pressing the "Terminate Process" button.
You can also export the list of processes to a .csv file, in order to keep or give someone a detailed report about your port usage.
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http://www.tamos.com/products/nettools/
http://essential-nettools.software.informer.com/

Essential NetTools is a set of network tools for diagnosing networks and monitoring your computer's network connections.
NetStat: displays the list of your computer's network connections, information on open TCP and UDP ports, IP address, and connection states. The program can map open ports to the owning application.
NBScan: a powerful and fast NetBIOS scanner. This tool features parallel scanning, which allows checking a class C network in less than one minute.
PortScan: an advanced TCP port scanner that allows you to scan your network for active ports. This tool features both conventional (full connect) and stealth (half-open) scanning modes.
Shares: monitors and logs external connections to your computer's shared resources, lists local shares, as well as allows to connect to remote resources that gives Windows 98/Me users NT user-level connectivity.
SysFiles: a convenient editor for the system files: services, protocol, networks, hosts, and lmhosts.
NetAudit (NetBIOS Auditing Tool): allows you to perform security checks on your network and/or individual computers offering the NetBIOS file sharing service.
RawSocket: provides you with the ability to establish low-level TCP and UDP connections to troubleshoot and test different networking services.
TraceRoute and Ping: these familiar utilities featuring customizable options and a convenient results presentation.
NSLookup: allows you to convert IP addresses to hostnames and perform advanced DNS queries.
ProcMon: displays the list of running processes. With this tool, you can identify hidden applications, kill running processes, manage your PC's resources more effectively.
SNMPAudit: an SNMP device scanner that can discover SNMP devices in the selected network segment and receive customizable data from each of the devices.

Other features include report generation in various formats;
a System Summary window.

What's new in version 4.2

New network tools have been added: HostAlive for service availability monitoring;
EmailVerify for checking if an e-mail address is valid by communicating with the corresponding mail server;
IPBlackList for checking if an IP address is included in various IP address black lists

Publisher's description

TamoSoft develops cutting-edge security and network monitoring software for the Internet and Local Area Networks, providing clients with the ability and confidence to meet the challenges of tomorrow's technology. Keeping pace with the industry trends, we offer professional tools that support the latest standards, protocols, software, and hardware for both wired and wireless networks.

Network scanners

softperfect.com/products/networkscanner/

SoftPerfect Network Scanner is a free multi-threaded IP, NetBIOS and SNMP scanner with a modern interface and many advanced features. It is intended for both system administrators and general users interested in computer security. The program pings computers, scans for listening TCP/UDP ports and displays which types of resources are shared on the network (including system and hidden).
In addition, it allows you to mount shared folders as network drives, browse them using Windows Explorer, filter the results list and more. SoftPerfect Network Scanner can also check for a user-defined port and report back if one is open. It can also resolve host names and auto-detect your local and external IP range. It supports remote shutdown and Wake-On-LAN.

Key features

• Pings computers and displays those alive.
• Detects hardware MAC-addresses, even across routers.
• Detects hidden shared folders and writable ones.
• Detects your internal and external IP addresses.
• Scans for listening TCP ports, some UDP and SNMP services.
• Retrieves currently logged-on users, configured user accounts, uptime, etc.
• You can mount and explore network resources.
• Can launch external third party applications.
• Exports results to HTML, XML, CSV and TXT
• Supports Wake-On-LAN, remote shutdown and sending network messages.
• Retrieves potentially any information via WMI.
• Retrieves information from remote registry, file system and service manager.
• It is absolutely free, requires no installation, and does not contain any adware/spyware/malware.

ScreenshotsDownload Network Scanner
Size: 2.0M
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http://autoscan-network.com/

AutoScan-Network is a network scanner (discovering and managing application). No configuration is required to scan your network. The main goal is to print the list of connected equipments in your network. System Requirements : •Mac OS X 10.5 or later •Microsoft Windows (XP, Vista) •GNU/Linux •Maemo 4 •Sun OpenSolaris

 • Fast network scanner
 • Automatic network discovery
 • TCP/IP scanner
 • Wake on lan functionality
 • Multi-threaded Scanner
 • Port scanner
 • Low surcharge on the network
 • VNC Client
 • Telnet Client
 • SNMP scanner
 • Simultaneous subnetworks scans without human intervention
 • Realtime detection of any connected equipment
 • Supervision of any equipment (router, server, firewall...)
 • Supervision of any network service (smtp, http, pop, ...)
 • Automatic detection of known operatic system (brand and version), you can also add any unknown equipment to the database
 • The graphical interface can connect one or more scanner agents (local or remote)
 • Scanner agents could be deployed all over the network to scan through any type of equipment (router, NAT, etc)
 • Network Intruders detection (in intruders detection mode, all new equipments blacklisted)
 • Complete network tree can be saved in a XML file.
 • Privileged account is not required

List of open ports in a OS

Source
Linux distributions
As with FreeBSD, the obvious choice of tool to use for listing open ports is netstat. Most Linux distributions use a different version of the utility, however — maintained separately from the Linux distribution, as an independent software development project.One consequence of that fact is that the command line options used to achieve the same results may be different with FreeBSD than with Debian, Ubuntu, or Fedora Core Linux systems. On a typical Linux system, this command will list open network ports and the processes that own them:

  netstat -lnptu

The output should look something like this:

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address   Foreign Address  State   PID/Program name
tcp        0      0 127.0.0.1:631   0.0.0.0:*        LISTEN  2458/cupsd
tcp        0      0 127.0.0.1:5432  0.0.0.0:*        LISTEN  2353/postgres
tcp6       0      0 :::22           :::*             LISTEN  2335/sshd
udp        0      0 0.0.0.0:631     0.0.0.0:*                2458/cupsd

As you can see from this output, the Debian GNU/Linux system on which I ran that command has only four open ports — two for CUPS, so that the computer can communicate with the network printer; one for PostgreSQL so that it can be contacted by applications in development; SSH, so that I can access it remotely, from my laptop.

Microsoft Windows XP Microsoft Windows also offers a netstat command that can be executed from the command line to get a list of open ports. The standard MS Windows version of netstat is slightly more limited than its Unix-like system counterparts, but still suffices to get a listing of listening services:

  netstat -a | find "LISTENING"

The output of this command should look something like this:

TCP    hostname:epmap           hostname:0               LISTENING
TCP    hostname:microsoft-ds    hostname:0               LISTENING
TCP    hostname:10110           hostname:0               LISTENING
TCP    hostname:netbios-ssn     hostname:0               LISTENING

. . . with “hostname” replaced by the system’s hostname, of course.
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Source

the following command will list all ports in use on the machine:

netstat -a

The output contains the protocol, local address, foreign address and current state
Netstat documentation on microsoft.com
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Designed for testing ports:
Portqry.exe
"Portqry.exe is a command-line utility that you can use to help troubleshoot TCP/IP connectivity issues. Portqry.exe runs on Windows 2000-based computers, on Windows XP-based computers, and on Windows Server 2003-based computers. The utility reports the port status of TCP and UDP ports on a computer that you select. "
Portqry.exe reports the status of a TCP/IP port in one of the following three ways:

• Listening
  
  A process is listening on the port on the computer that you selected. Portqry.exe received a response from the port.
• Not Listening
  
  No process is listening on the target port on the target system. Portqry.exe received an Internet Control Message Protocol (ICMP) "Destination Unreachable - Port Unreachable" message back from the target UDP port. Or if the target port is a TCP port, Portqry received a TCP acknowledgement packet with the Reset flag set.
• Filtered
  
  The port on the computer that you selected is being filtered. Portqry.exe did not receive a response from the port. A process may or may not be listening on the port. By default, TCP ports are queried three times, and UDP ports are queried one time before a report indicates that the port is filtered.

Portqry.exe can query a single port, an ordered list of ports, or a sequential range of ports.
Examples 

The following command tries to resolve "reskit.com" to an IP address and then queries TCP port 25 on the corresponding host:

portqry -n reskit.com -p tcp -e 25

The following command tries to resolve "169.254.0.11" to a host name and then queries TCP ports 143,110, and 25 (in that order) on the host that you selected. This command also creates a log file (Portqry.log) that contains a log of the command that you ran and its output.

portqry -n 169.254.0.11 -p tcp -o 143,110,25 -l portqry.log

The following command tries to resolve my_server to an IP address and then queries the specified range of UDP ports (135-139) in sequential order on the corresponding host. This command also creates a log file (my_server.txt) that contains a log of the command that you ran and its output.

portqry -n my_server -p udp -r 135:139 -l my_server.txt

Portqry.exe is available for download from the Microsoft Download Center. To download Portqry.exe, visit the following Microsoft Web site: 

http://www.microsoft.com/downloads/details.aspx?familyid=89811747-C74B-4638-A2D5-AC828BDC6983&displaylang=en

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telnet [ipaddress] [portnumber]
Fill in the address/port. If you connect, you know the port is open, assuming it's a TCP service. Doesn't work for UDP
You could also use nmap to see all of the open ports on a given machine.

Stealth Ports in Comodo firewall

Source
Port Stealthing is a security feature whereby ports on an Internet connected PC are hidden from sight, evoking no response to opportunistic port scans.

Nmap

Quelle

Portscanner, sucht übers Netzwerk nach offenen TCP- und UDP-Ports auf anderen Rechnern

Nmap im Artikel aus c't 10/2008: Nmap ist wohl der bekannteste Netzwerkscanner. Er spürt aktive Hosts im Netz auf und nutzt eine breite Palette an Tests vom normalen TCP/IP-Handshake bis zum verborgenen TCP-FIN-Scan. Aufgrund der Eigenheiten der TCP/IP-Stacks erkennt nmap das Betriebssystem. Die im Paket enthaltene grafische Oberfläche Zenmap hilft beim Zusammenstellen der Optionen des Kommandozeilenprogramms. (Stefan Hoffmann/ je)

Weitere Artikel:
c't 14/2007
c't 4/2006
c't 23/2005
c't 9/2003
c't 14/2001
c't 14/2000

Nmap im Themen-Special Mac's Finest (1): ... Nmap heißt ein mächtiger Port-Scanner für die Kommandozeile. Er findet nicht nur heraus, ob im lokalen Netz oder auf der Internetseite des Routers ungewollt Dienste offen stehen, ob ein Rechner über das Netzwerk nutzbare Sicherheitslücken aufweist oder welche Dienste eine unbekannte Station im Netz anbietet, sondern erkennt in der Regel auch Server- und Betriebssystemversionen. (je) weiterlesen