Nmap
"Nmap ("Network Mapper") is a free and open source (license) utility for network exploration or security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. It was designed to rapidly scan large networks, but works fine against single hosts."
Example
root@fritz:/var/media/ftp/uData# nmap localhost Starting Nmap 4.68 ( http://nmap.org ) at 2011-04-20 09:06 CEST Interesting ports on localhost (127.0.0.1): Not shown: 1699 closed ports PORT STATE SERVICE 21/tcp open ftp 22/tcp open ssh 23/tcp open telnet 53/tcp open domain 80/tcp open http 81/tcp open hosts2-ns 111/tcp open rpcbind 443/tcp open https 1011/tcp open unknown 1012/tcp open unknown 2007/tcp open dectalk 2047/tcp open dls 5060/tcp open sip 8080/tcp open http-proxy 8123/tcp open polipo 8888/tcp open sun-answerbook Nmap done: 1 IP address (1 host up) scanned in 4.598 seconds
Known open ports
| Port | Function | Program/process | Anmerkung |
| 81 | Freetz! | inetd | |
| 82 | AVM's Webfilter | contfiltd | bei Firmware 7270 05.05 auf Port 81 |
| 111 | portmapper (nfs) | portmap | |
| 1011 | AVM's telefon-daemon | telefon | |
| 1012 | AVM's telefon-daemon | telefon | |
| 2007 | ??? | telefon | |
| 2047 | nfs v3 | nfsd | |
| 8080 | AVM's Kindersicherung | ctlmgr.bin | |
| 8888 | AVM's telefon-daemon | telefon |
Useful command:
netstat -anp