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- tcp_scan and udp_scan are tools to scan a host for available network
- services (for example, to see if your packet filter does its job). You
- can scan specific services or ranges of ports. In order to speed up
- the process, the tools probe a bunch of network ports in parallel.
-
- The programs work with SunOS 4.1.3, SunOS 5.3 (Solaris 2.3) and
- probably with anything that looks like 4.3+ BSD or System V.4.
-
- There is one catch, though: the programs use raw ICMP sockets, so they
- need to be run with root privilege. Raw ICMP sockets are used to work
- around common shortcomings in BSD (75-second timeout on a non-blocking
- TCP connect() to an unreachable host) and in SYSV (a connected UDP
- socket does not pass delivery errors back to the application).
-
- Warning: these programs will raise lots of alarms on sites that run my
- tcp wrapper or that do any other kind of network monitoring. Use the
- programs only with prior permission from the affected sites.
-
- Wietse Venema
-