.\"
.\" Copyright (c) 1998 David E. O'Brien
.\"
.\" All rights reserved.
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.\" $FreeBSD$
.\"
.\" .TH NMAP 1L local
.Dd August 4, 1998
.Dt NMAP 1
.Os BSD
.Sh NAME
.Nm nmap
.Nd network port scanner
.Sh SYNOPSIS
.Nm nmap
.Op Ar options
.Ar hostname
.Op Ar /mask
.Sh DESCRIPTION
.Nm
is a utility for port scanning large networks, although it works fine for
single hosts. The guiding philosophy for the creation of 
.Nm
was TMTOWTDI (There's More Than One Way To Do It). This is the Perl slogan, but
it is equally applicable to scanners. Sometimes you need speed, other times you
may need stealth. In some cases, bypassing firewalls may be required. Not to
mention the fact that you may want to scan different protocols (UDP, TCP, ICMP,
etc.). You just can't do all this with one scanning mode. And you don't want to
have 10 different scanners around, all with different interfaces and
capabilities. Thus
.Nm 
incorporats virtually every scanning technique known.
Specifically, 
.Nm 
supports:

      Vanilla TCP connect() scanning, 
      TCP SYN (half open) scanning, 
      TCP FIN (stealth) scanning, 
      TCP ftp proxy (bounce attack) scanning 
      SYN/FIN scanning using IP fragments (bypasses packet filters), 
      UDP recvfrom() scanning, 
      UDP raw ICMP port unreachable scanning, 
      ICMP scanning (ping-sweep), and 
      Reverse-ident scanning. 

.Nm
also supports a number of performance and reliability features such as dynamic
delay time calculations, packet timeout and retransmission, parallel port
scanning, detection of down hosts via parallel pings, and flexible target and
port specification. 
.Sh FILES
none.
.Sh SEE ALSO
.Xr mscan 1L ,
.Xr nc 1L ,
.Xr scrobe 1L
.Sh DIAGNOSTICS
none.
.Sh BUGS
none known.
.Sh AUTHORS
This man page has been written by David O'Brien (obrien@cs.ucdavis.edu)
.\" .Sh HISTORY
.\" .Nm 
.\" appeared in FreeBSD 3.0.