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<TITLE>Nmap network security scanner man page</TITLE>
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<H1>Nmap network security scanner man page</H1>
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<B>NMAP(1)</B>                                                                <B>NMAP(1)</B>




</PRE>
<H2>NAME</H2><PRE>
       nmap - Network exploration tool and security scanner


</PRE>
<H2>SYNOPSIS</H2><PRE>
       <B>nmap</B> [Scan Type(s)] [Options] &lt;host or net #1 ... [#N]&gt;


</PRE>
<H2>DESCRIPTION</H2><PRE>
       <I>Nmap</I> is designed to allow system administrators and curious individuals
       to scan large networks to determine which hosts are up  and  what  ser-
       vices  they  are  offering.   <I>nmap</I>  supports a large number of scanning
       techniques such as: UDP, TCP connect(), TCP SYN (half open), ftp  proxy
       (bounce  attack),  ICMP  (ping  sweep),  FIN, ACK sweep, Xmas Tree, SYN
       sweep, IP Protocol, and Null scan.  See the <I>Scan</I> <I>Types</I> section for more
       details.  nmap also offers a number of advanced features such as remote
       OS detection via TCP/IP fingerprinting, stealth scanning, dynamic delay
       and  retransmission  calculations, parallel scanning, detection of down
       hosts via parallel pings, decoy  scanning,  port  filtering  detection,
       direct (non-portmapper) RPC scanning, fragmentation scanning, and flex-
       ible target and port specification.

       Significant effort has been put into decent nmap performance  for  non-
       root  users.   Unfortunately,  many critical kernel interfaces (such as
       raw sockets) require root privileges.  nmap should be run as root when-
       ever possible (not setuid root, of course).

       The  result  of  running nmap is usually a list of interesting ports on
       the machine(s) being scanned (if any).  Nmap always  gives  the  port’s
       "well  known"  service name (if any), number, state, and protocol.  The
       state is either "open", "filtered", or "unfiltered".  Open  means  that
       the  target  machine  will accept() connections on that port.  Filtered
       means that a firewall, filter, or other network  obstacle  is  covering
       the port and preventing nmap from determining whether the port is open.
       Unfiltered means that the port is known by nmap to  be  closed  and  no
       firewall/filter  seems to be interfering with nmap’s attempts to deter-
       mine this.  Unfiltered ports are the common case  and  are  only  shown
       when most of the scanned ports are in the filtered state.

       Depending  on  options used, nmap may also report the following charac-
       teristics of the remote host: OS in use, TCP  sequentiality,  usernames
       running  the  programs  which  have  bound  to each port, the DNS name,
       whether the host is a smurf address, and a few others.


</PRE>
<H2>OPTIONS</H2><PRE>
       Options that make sense  together  can  generally  be  combined.   Some
       options  are  specific  to certain scan modes.  <I>nmap</I> tries to catch and
       warn the user about psychotic or unsupported option combinations.

       If you are impatient, you can skip to the <I>examples</I> section at the  end,
       which  demonstrates common usage.  You can also run <B>nmap</B> <B>-h</B> for a quick
       reference page listing all the options.

       <B>SCAN</B> <B>TYPES</B>

       <B>-sS</B>    TCP SYN scan: This technique is often referred to as "half-open"
              scanning, because you don’t open a full TCP connection. You send
              a SYN packet, as if you are going to open a real connection  and
              you wait for a response. A SYN|ACK indicates the port is listen-
              ing. A RST is indicative of a non-listener.   If  a  SYN|ACK  is
              received,  a RST is immediately sent to tear down the connection
              (actually our OS kernel does this for us). The primary advantage
              to  this  scanning  technique  is  that fewer sites will log it.
              Unfortunately you need root privileges to build these custom SYN
              packets.  This is the default scan type for privileged users.

       <B>-sT</B>    TCP connect() scan: This is the most basic form of TCP scanning.
              The connect() system call provided by your operating  system  is
              used  to  open  a  connection  to  every interesting port on the
              machine. If the port is listening, connect() will succeed,  oth-
              erwise  the  port  isn’t reachable. One strong advantage to this
              technique is that you don’t need  any  special  privileges.  Any
              user on most UNIX boxes is free to use this call.

              This  sort of scan is easily detectable as target host logs will
              show a bunch of connection and error messages for  the  services
              which  accept() the connection just to have it immediately shut-
              down.  This is the default scan type for unprivileged users.

       <B>-sF</B> <B>-sX</B> <B>-sN</B>
              Stealth FIN, Xmas Tree, or Null scan modes: There are times when
              even  SYN  scanning isn’t clandestine enough. Some firewalls and
              packet filters watch for SYNs to restricted ports, and  programs
              like Synlogger and Courtney are available to detect these scans.
              These advanced scans, on the other hand, may  be  able  to  pass
              through unmolested.

              The  idea  is  that  closed  ports are required to reply to your
              probe packet with an RST, while open ports must ignore the pack-
              ets  in  question (see RFC 793 pp 64).  The FIN scan uses a bare
              (surprise) FIN packet as the probe, while  the  Xmas  tree  scan
              turns  on the FIN, URG, and PUSH flags.  The Null scan turns off
              all flags.  Unfortunately Microsoft (like usual) decided to com-
              pletely  ignore  the standard and do things their own way.  Thus
              this scan type  will  not  work  against  systems  running  Win-
              dows95/NT.   On the positive side, this is a good way to distin-
              guish between the two platforms.  If the scan finds open  ports,
              you  know the machine is not a Windows box.  If a -sF,-sX,or -sN
              scan shows all ports closed, yet a SYN (-sS)  scan  shows  ports
              being  opened,  you are probably looking at a Windows box.  This
              is less useful now that nmap has proper OS detection  built  in.
              There  are  also a few other systems that are broken in the same
              way Windows is.  They include Cisco, BSDI, HP/UX, MVS, and IRIX.
              All  of  the  above  send  resets  from the open ports when they
              should just drop the packet.

       <B>-sP</B>    Ping scanning: Sometimes you only want to know which hosts on  a
              network  are  up.  Nmap can do this by sending ICMP echo request
              packets to every IP address on the networks you specify.   Hosts
              that   respond  are  up.   Unfortunately,  some  sites  such  as
              microsoft.com block echo request packets.  Thus  nmap  can  also
              send a TCP ack packet to (by default) port 80.  If we get an RST
              back, that machine is up.  A third technique involves sending  a
              SYN  packet  and  waiting  for a RST or a SYN/ACK.  For non-root
              users, a connect() method is used.

              By default (for root users), nmap uses both  the  ICMP  and  ACK
              techniques  in parallel.  You can change the <B>-P</B> option described
              later.

              Note that pinging is done by default anyway, and only hosts that
              respond  are  scanned.  Only use this option if you wish to ping
              sweep <B>without</B> doing any actual port scans.

       <B>-sV</B>    Version detection: Afer TCP  and/or  UDP  ports  are  discovered
              using  one of the other scan methods, version detection communi-
              cates with those ports to try and determine more about  what  is
              actually  running.  A file called nmap-service-probes is used to
              determine the best probes for detecting various services and the
              match  strings  to  expect.  Nmap tries to determine the service
              protocol (e.g. ftp, ssh, telnet,  http),  the  application  name
              (e.g. ISC Bind, Apache httpd, Solaris telnetd), the version num-
              ber, and sometimes  miscellaneous  details  like  whether  an  X
              server  is open to connections or the SSH protocol version).  If
              Nmap was compiled with OpenSSL support, it will connect  to  SSL
              servers  to  deduce the service listening behind the encryption.
              When RPC services are discovered, the Nmap RPC grinder  is  used
              to  determine  the  RPC  program  and version numbers.  Some UDP
              ports are left in the "open|filtered" state after a UDP scan  is
              unable  to determine whether the port is open or filtered.  Ver-
              sion detection will try to elicit a response  from  these  ports
              (just  as it does with open ports), and change the state to open
              if it succeeds. Note that the Nmap -A option also  enables  this
              feature.   For  a much more detailed description of Nmap service
              detection, read our paper  at  http://www.insecure.org/nmap/ver-
              sionscan.html .  There is a related --version_trace option which
              causes Nmap to print out extensive  debugging  info  about  what
              version  scanning  is  doing (this is a subset of what you would
              get with --packet_trace).

       <B>-sU</B>    UDP scans: This method is used  to  determine  which  UDP  (User
              Datagram Protocol, RFC 768) ports are open on a host.  The tech-
              nique is to send 0 byte UDP packets to each port on  the  target
              machine.   If  we receive an ICMP port unreachable message, then
              the port is closed.  If a UDP response is received to the  probe
              (unusual),  the port is open.  If we get no response at all, the
              state is "open|filtered", meaning that the port is  either  open
              or packet filters are blocking the communication.  Versions scan
              (-sV) can be used to help differentiate  the  truly  open  ports
              from the filtered ones.

              Some  people  think  UDP scanning is pointless. I usually remind
              them of the Solaris rpcbind hole. Rpcbind can be found hiding on
              an  undocumented  UDP  port somewhere above 32770. So it doesn’t
              matter that 111 is blocked by the firewall.  But  can  you  find
              which  of  the  more  than 30,000 high ports it is listening on?
              With a UDP scanner you can!  There is also the cDc Back  Orifice
              backdoor  program which hides on a configurable UDP port on Win-
              dows machines.  Not to mention the many commonly vulnerable ser-
              vices that utilize UDP such as snmp, tftp, NFS, etc.

              Unfortunately  UDP  scanning  is  sometimes painfully slow since
              most hosts implement a suggestion in RFC 1812 (section  4.3.2.8)
              of limiting the ICMP error message rate.  For example, the Linux
              kernel (in net/ipv4/icmp.h) limits destination unreachable  mes-
              sage  generation  to 80 per 4 seconds, with a 1/4 second penalty
              if that is exceeded.  Solaris has much more strict limits (about
              2 messages per second) and thus takes even longer to scan.  <I>nmap</I>
              detects this rate limiting and slows  down  accordingly,  rather
              than flood the network with useless packets that will be ignored
              by the target machine.

              As is typical, Microsoft ignored the suggestion of the  RFC  and
              does  not  seem  to  do any rate limiting at all on Win95 and NT
              machines.  Thus we can scan all 65K ports of a  Windows  machine
              <B>very</B> quickly.  Whoop!


       <B>-sO</B>    IP  protocol  scans:  This  method is used to determine which IP
              protocols are supported on a host.  The technique is to send raw
              IP packets without any further protocol header to each specified
              protocol on the target machine.  If we receive an ICMP  protocol
              unreachable message, then the protocol is not in use.  Otherwise
              we assume it is open.  Note that some hosts (AIX, HP-UX, Digital
              UNIX)  and firewalls may not send protocol unreachable messages.
              This causes all of the protocols to appear "open".

              Because the implemented technique is very similar  to  UDP  port
              scanning,  ICMP  rate limit might apply too. But the IP protocol
              field has only 8 bits, so at most 256 protocols  can  be  probed
              which should be possible in reasonable time anyway.

       <B>-sI</B> <B>&lt;zombie</B> <B>host[:probeport]&gt;</B>
              Idlescan: This advanced scan method allows for a truly blind TCP
              port scan of the target (meaning no packets are sent to the tar-
              get  from your real IP address).  Instead, a unique side-channel
              attack exploits predictable "IP fragmentation ID" sequence  gen-
              eration  on  the zombie host to glean information about the open
              ports on the target.  IDS systems will display the scan as  com-
              ing  from  the  zombie machine you specify (which must be up and
              meet certain criteria).  I wrote an informal  paper  about  this
              technique at http://www.insecure.org/nmap/idlescan.html .

              Besides   being  extraordinarily  stealthy  (due  to  its  blind
              nature), this scan type permits mapping out IP-based trust rela-
              tionships  between  machines.  The port listing shows open ports
              <I>from</I> <I>the</I> <I>perspective</I> <I>of</I> <I>the</I> <I>zombie</I> <I>host.</I>  So you can  try  scan-
              ning  a  target  using  various  zombies that you think might be
              trusted (via router/packet filter  rules).   Obviously  this  is
              crucial  information  when  prioritizing attack targets.  Other-
              wise, you penetration testers might have to expend  considerable
              resources "owning" an intermediate system, only to find out that
              its IP isn’t even trusted by the  target  host/network  you  are
              ultimately after.

              You  can  add  a  colon followed by a port number if you wish to
              probe a particular port on the zombie  host  for  IPID  changes.
              Otherwise  Nmap  will  use  the port it uses by default for "tcp
              pings".

       <B>-sA</B>    ACK scan: This advanced method is usually used to map out  fire-
              wall  rulesets.   In particular, it can help determine whether a
              firewall is stateful or just a simple packet filter that  blocks
              incoming SYN packets.

              This scan type sends an ACK packet (with random looking acknowl-
              edgment/sequence numbers) to the  ports  specified.   If  a  RST
              comes back, the ports is classified as "unfiltered".  If nothing
              comes back (or if an ICMP unreachable is returned), the port  is
              classified  as "filtered".  Note that <I>nmap</I> usually doesn’t print
              "unfiltered" ports, so getting <B>no</B> ports shown in the  output  is
              usually  a  sign  that  all the probes got through (and returned
              RSTs). This scan will obviously never show ports in  the  "open"
              state.

       <B>-sW</B>    Window scan: This advanced scan is very similar to the ACK scan,
              except that it can sometimes detect open ports as well  as  fil-
              tered/unfiltered  due  to  an  anomaly  in  the  TCP window size
              reporting by some operating systems.  Systems vulnerable to this
              include  at least some versions of AIX, Amiga, BeOS, BSDI, Cray,
              Tru64 UNIX, DG/UX, OpenVMS, Digital UNIX, FreeBSD, HP-UX,  OS/2,
              IRIX,  MacOS,  NetBSD,  OpenBSD,  OpenStep, QNX, Rhapsody, SunOS
              4.X, Ultrix, VAX, and VxWorks.   See  the  nmap-hackers  mailing
              list archive for a full list.

       <B>-sR</B>    RPC  scan.   This  method  works in combination with the various
              port scan methods of Nmap.  It takes all the TCP/UDP ports found
              open  and  then floods them with SunRPC program NULL commands in
              an attempt to determine whether they are RPC ports, and  if  so,
              what  program  and  version  number they serve up.  Thus you can
              effectively obtain the same info as "rpcinfo  -p"  even  if  the
              target’s  portmapper  is  behind a firewall (or protected by TCP
              wrappers).  Decoys do not currently work with RPC scan, at  some
              point  I may add decoy support for UDP RPC scans.  This is auto-
              matically enabled as part of version scan (-sV) if  you  request
              that.

       <B>-sL</B>    List scan.  This method simply generates and prints a list of IP
              addresses or hostnames without actually pinging or port scanning
              them.   DNS name resolution will be performed unless you use -n.

       <B>-b</B> <B>&lt;ftp</B> <B>relay</B> <B>host&gt;</B>
              FTP bounce attack: An interesting "feature" of the ftp  protocol
              (RFC  959)  is  support  for  "proxy"  ftp connections. In other
              words, I should be able to connect  from  evil.com  to  the  FTP
              server  of  target.com  and  request that the server send a file
              ANYWHERE on the Internet!  Now this may have worked well in 1985
              when the RFC was written. But in today’s Internet, we can’t have
              people hijacking ftp servers and requesting that  data  be  spit
              out  to arbitrary points on the Internet. As *Hobbit* wrote back
              in 1995, this protocol flaw  "can  be  used  to  post  virtually
              untraceable  mail  and news, hammer on servers at various sites,
              fill up disks, try to hop firewalls, and generally  be  annoying
              and  hard  to track down at the same time." What we will exploit
              this for is to  (surprise,  surprise)  scan  TCP  ports  from  a
              "proxy"  ftp  server.  Thus  you  could connect to an ftp server
              behind a firewall, and then scan ports that are more  likely  to
              be blocked (139 is a good one). If the ftp server allows reading
              from and writing to some directory (such as /incoming), you  can
              send arbitrary data to ports that you do find open (nmap doesn’t
              do this for you though).

              The argument passed to the "b" option is the host  you  want  to
              use  as a proxy, in standard URL notation.  The format is: <I>user-</I>
              <I>name:password@server:port.</I>  Everything but <I>server</I>  is  optional.
              To determine what servers are vulnerable to this attack, you can
              see my article in <I>Phrack</I> 51.  An updated version is available at
              the <I>nmap</I> URL (http://www.insecure.org/nmap).

       <B>GENERAL</B> <B>OPTIONS</B>
              None  of  these are required but some can be quite useful.  Note
              that the -P options can now be combined -- you can increase your
              odds of penetrating strict firewalls by sending many probe types
              using different TCP ports/flags and ICMP codes.

       <B>-P0</B>    Do not try to ping hosts at  all  before  scanning  them.   This
              allows  the  scanning  of  networks  that  don’t allow ICMP echo
              requests (or responses) through their  firewall.   microsoft.com
              is  an example of such a network, and thus you should always use
              <B>-P0</B> or <B>-PS80</B> when portscanning microsoft.com.  Note  tht  "ping"
              in  this context may involve more than the traditional ICMP echo
              request packet.  Nmap supports many such probes, including arbi-
              trary  combinations  of  TCP, UDP, and ICMP probes.  By default,
              Nmap sends an ICMP echo request and a TCP ACK packet to port 80.

       <B>-PA</B> <B>[portlist]</B>
              Use  TCP  ACK "ping" to determine what hosts are up.  Instead of
              sending ICMP echo request packets and waiting for a response, we
              spew  out TCP ACK packets throughout the target network (or to a
              single machine) and then wait for  responses  to  trickle  back.
              Hosts  that  are up should respond with a RST.  This option pre-
              serves the efficiency of only scanning hosts that are  up  while
              still  allowing you to scan networks/hosts that block ping pack-
              ets.  For non root UNIX users, we use connect() and thus  a  SYN
              is  actually  being  sent.   To set the destination ports of the
              probe packets use -PA&lt;port1&gt;[,port2][...].  The default port  is
              80,  since  this port is often not filtered out.  Note that this
              option now accepts multiple, comma-separated port numbers.

       <B>-PS</B> <B>[portlist]</B>
              This option uses SYN (connection request) packets instead of ACK
              packets for root users.  Hosts that are up should respond with a
              RST (or, rarely, a SYN|ACK).  You can set the destination  ports
              in the same manner as -PA above.

       <B>-PU</B> <B>[portlist]</B>
              This  option  sends UDP probes to the specified hosts, expecting
              an ICMP port unreachable packet (or possibly a UDP  response  if
              the  port  is  open) if the host is up.  Since many UDP services
              won’t reply to an empty packet, your best bet might be  to  send
              this to expected-closed ports rather than open ones.

       <B>-PE</B>    This  option  uses  a  true ping (ICMP echo request) packet.  It
              finds hosts that are  up  and  also  looks  for  subnet-directed
              broadcast  addresses  on  your  network.  These are IP addresses
              which are externally reachable and translate to a  broadcast  of
              incoming  IP  packets to a subnet of computers.  These should be
              eliminated if found as they allow for numerous denial of service
              attacks (Smurf is the most common).

       <B>-PP</B>    Uses  an ICMP timestamp request (type 13) packet to find listen-
              ing hosts.

       <B>-PM</B>    Same as <B>-PE</B> and <B>-PP</B> except uses a  netmask  request  (ICMP  type
              17).

       <B>-PB</B>    This is the default ping type.  It uses both the ACK ( <B>-PA</B> ) and
              ICMP echo request ( <B>-PE</B> ) sweeps in parallel.  This way you  can
              get  firewalls  that  filter either one (but not both).  The TCP
              probe destination port can be set in the same manner as with -PA
              above.   Note that this flag is now deprecated as pingtype flags
              can now be used in combination.  So you should use both "PE" and
              "PA"  (or  rely  on  the  default behavior) to achieve this same
              effect.

       <B>-O</B>     This option activates remote host identification via TCP/IP fin-
              gerprinting.   In  other words, it uses a bunch of techniques to
              detect subtleties in the  underlying  operating  system  network
              stack  of the computers you are scanning.  It uses this informa-
              tion to create  a  "fingerprint"  which  it  compares  with  its
              database  of  known  OS  fingerprints  (the nmap-os-fingerprints
              file) to decide what type of system you are scanning.

              If Nmap is unable to guess the OS of a machine,  and  conditions
              are  good (e.g. at least one open port), Nmap will provide a URL
              you can use to submit the fingerprint if you know (for sure) the
              OS  running on the machine.  By doing this you contribute to the
              pool of operating systems known to nmap and thus it will be more
              accurate  for everyone.  Note that if you leave an IP address on
              the form, the machine may be scanned when we add the fingerprint
              (to validate that it works).

              The  -O  option  also  enables  several other tests.  One is the
              "Uptime" measurement, which uses the TCP timestamp  option  (RFC
              1323)  to  guess when a machine was last rebooted.  This is only
              reported for machines which provide this information.

              Another test enabled by -O is TCP Sequence Predictability  Clas-
              sification.   This is a measure that describes approximately how
              hard it is to establish a  forged  TCP  connection  against  the
              remote  host.   This  is  useful  for exploiting source-IP based
              trust relationships (rlogin, firewall filters, etc) or for  hid-
              ing  the  source  of an attack.  The actual difficulty number is
              based  on  statistical  sampling  and  may  fluctuate.   It   is
              generally better to use the English classification such as "wor-
              thy challenge" or "trivial joke".  This is only reported in nor-
              mal output with -v.

              When  verbose  mode (-v) is on with -O, IPID Sequence Generation
              is also reported.  Most machines are in the "incremental" class,
              which  means that they increment the "ID" field in the IP header
              for each packet they send.  This makes them vulnerable  to  sev-
              eral advanced information gathering and spoofing attacks.

       <B>--osscan_limit</B>
              OS  detection is far more effective if at least one open and one
              closed TCP port are found.  Set this option and  Nmap  will  not
              even try OS detection against hosts that do not meet this crite-
              ria.  This can save substantial time, particularly on -P0  scans
              against  many  hosts.   It  only  matters  when  OS detection is
              requested (-O or -A options).

       <B>-A</B>     This option enables  _a_dditional  _a_dvanced  and  _a_ggressive
              options.   I haven’t decided exactly which it stands for yet :).
              Presently this enables OS Detection (-O)  and  version  scanning
              (-sV).   More features may be added in the future.  The point is
              to enable a comprehensive set of  scan  options  without  people
              having  to  remember  a  large  set  of flags.  This option only
              enables features, and not timing options (such as -T4)  or  ver-
              bosity options (-v) that you might wan’t as well.

       <B>-6</B>     This  options enables IPv6 support.  All targets must be IPv6 if
              this option is used, and they can be specified  via  normal  DNS
              name   (AAAA  record)  or  as  a  literal  IP  address  such  as
              3ffe:501:4819:2000:210:f3ff:fe03:4d0 .  Currently, connect() TCP
              scan and TCP connect() Ping scan are supported.  If you need UDP
              or  other  scan  types,  have  a  look  at  http://nmap6.source-
              forge.net/ .

       <B>-f</B>     This option causes the requested SYN, FIN, XMAS, or NULL scan to
              use tiny fragmented IP packets.  The idea is to split up the TCP
              header  over  several  packets to make it harder for packet fil-
              ters, intrusion  detection  systems,  and  other  annoyances  to
              detect  what  you are doing. Be careful with this! Some programs
              have trouble handling these tiny packets.  My  favorite  sniffer
              segmentation   faulted  immediately  upon  receiving  the  first
              36-byte fragment. After that comes a 24  byte  one!  While  this
              method  won’t get by packet filters and firewalls that queue all
              IP fragments (like the  CONFIG_IP_ALWAYS_DEFRAG  option  in  the
              Linux  kernel),  some  networks can’t afford the performance hit
              this causes and thus leave it disabled.

              Note that I do not yet have this option working on all  systems.
              It  works fine for my Linux, FreeBSD, and OpenBSD boxes and some
              people have reported success with other *NIX variants.

       <B>-v</B>     Verbose mode.  This is a highly recommended option and it  gives
              out  more  information  about  what is going on.  You can use it
              twice for greater effect.  You can also use <B>-d</B> a  few  times  if
              you really want to get crazy with scrolling the screen!

       <B>-h</B>     This handy option display a quick reference screen of nmap usage
              options.  As you may have noticed, this man page is not  exactly
              a "quick reference" :)

       <B>-oN</B> <B>&lt;logfilename&gt;</B>
              This  logs  the results of your scans in a normal <B>human</B> <B>readable</B>
              form into the file you specify as an argument.

       <B>-oX</B> <B>&lt;logfilename&gt;</B>
              This logs the results of your scans in <B>XML</B> form  into  the  file
              you  specify  as  an  argument.   This allows programs to easily
              capture and interpret Nmap results.  You can give  the  argument
              "-"  (without  quotes)  to  shoot  output into stdout (for shell
              pipelines, etc).  In this case normal output will be suppressed.
              Watch out for error messages if you use this (they will still go
              to stderr).  Also note that "-v" may cause some  extra  informa-
              tion to be printed.  The Document Type Definition (DTD) defining
              the  XML  output  structure  is  available  at  http://www.inse-
              cure.org/nmap/data/nmap.dtd .

       <B>-oG</B> <B>&lt;logfilename&gt;</B>
              This  logs the results of your scans in a <B>grepable</B> form into the
              file you specify as an argument.  This  simple  format  provides
              all the information on one line (so you can easily grep for port
              or OS information and see all the IPs.  This used to be the pre-
              ferred  mechanism for programs to interact with Nmap, but now we
              recommend XML output (-oX instead).  This simple format may  not
              contain  as much information as the other formats.  You can give
              the argument "-" (without quotes) to shoot  output  into  stdout
              (for  shell pipelines, etc).  In this case normal output will be
              suppressed.  Watch out for error messages if you use this  (they
              will  still  go to stderr).  Also note that "-v" will cause some
              extra information to be printed.

       <B>-oA</B> <B>&lt;basefilename&gt;</B>
              This tells Nmap  to  log  in  ALL  the  major  formats  (normal,
              grepable,  and  XML).  You give a base for the filename, and the
              output files will be base.nmap, base.gnmap, and base.xml.

       <B>-oS</B> <B>&lt;logfilename&gt;</B>
              thIs l0gz th3 r3suLtS of YouR ScanZ iN a <B>s|&lt;ipT</B> <B>kiDd|3</B> f0rM iNto
              THe  fiL3  U sPecfy 4s an arGuMEnT!  U kAn gIv3 the 4rgument "-"
              (wItHOUt qUOteZ) to sh00t output iNT0 stDouT!@!!

       <B>--resume</B> <B>&lt;logfilename&gt;</B>
              A network scan that is canceled due to control-C,  network  out-
              age,  etc.  can  be  resumed using this option.  The logfilename
              must be either a normal (-oN) or grepable  (-oG)  log  from  the
              aborted  scan.   No other options can be given (they will be the
              same as the aborted scan).  Nmap will start on the machine after
              the last one successfully scanned in the log file.

       <B>--exclude</B> <B>&lt;host1</B> <B>[,host2][,host3],..."&gt;</B>
              Specifies  a  list  of  targets  (hosts, ranges, netblocks) that
              should be excluded from a scan. Useful  to  keep  from  scanning
              yourself, your ISP, particularly sensitive hosts, etc.

       <B>--excludefile</B> <B>&lt;exclude_file&gt;</B>
              Same  functionality  as  the --exclude option, only the excluded
              targets are provided in an newline-delimited exclude_file rather
              than on the command line.

       <B>--append_output</B>
              Tells  Nmap  to append scan results to any output files you have
              specified rather than overwriting those files.

       <B>-iL</B> <B>&lt;inputfilename&gt;</B>
              Reads target specifications from the file specified RATHER  than
              from  the  command line.  The file should contain a list of host
              or network expressions separated by spaces, tabs,  or  newlines.
              Use  a hyphen (-) as <I>inputfilename</I> if you want nmap to read host
              expressions from stdin (like at the end of  a  pipe).   See  the
              section <I>target</I> <I>specification</I> for more information on the expres-
              sions you fill the file with.

       <B>-iR</B> <B>&lt;num</B> <B>hosts&gt;</B>
              This option tells Nmap to generate its own hosts to scan by sim-
              ply  picking  random  numbers  :).   It will never end after the
              given number of IPs has been scanned -- use 0 for a never-ending
              scan.  This option can be useful for statistical sampling of the
              Internet to estimate various things.  If  you  are  ever  really
              bored,  try  <I>nmap</I> <I>-sS</I> <I>-PS80</I> <I>-iR</I> <I>0</I> <I>-p</I> <I>80</I> to find some web servers
              to look at.

       <B>-p</B> <B>&lt;port</B> <B>ranges&gt;</B>
              This option specifies what ports you want to specify. For  exam-
              ple  "-p  23"  will only try port 23 of the target host(s).  "-p
              20-30,139,60000-" scans ports between 20 and 30, port  139,  and
              all  ports greater than 60000.  The default is to scan all ports
              between 1 and 1024 as well as any ports listed in  the  services
              file  which  comes  with  nmap.  For IP protocol scanning (-sO),
              this specifies the protocol number you wish to scan for (0-255).

              When scanning both TCP and UDP ports, you can specify a particu-
              lar protocol by preceding the port numbers by "T:" or "U:".  The
              qualifier  lasts until you specify another qualifier.  For exam-
              ple, the argument  "-p  U:53,111,137,T:21-25,80,139,8080"  would
              scan  UDP ports 53,111,and 137, as well as the listed TCP ports.
              Note that to scan both UDP &amp; TCP, you have to specify -sU and at
              least  one TCP scan type (such as -sS, -sF, or -sT).  If no pro-
              tocol qualifier is given, the port numbers are added to all pro-
              tocol lists.

       <B>-F</B> <B>Fast</B> <B>scan</B> <B>mode.</B>
              Specifies  that  you  only  wish to scan for ports listed in the
              services file which comes with nmap (or the protocols  file  for
              -sO).   This  is  obviously  much faster than scanning all 65535
              ports on a host.

       <B>-D</B> <B>&lt;decoy1</B> <B>[,decoy2][,ME],...&gt;</B>
              Causes a decoy scan to be performed which makes it appear to the
              remote  host that the host(s) you specify as decoys are scanning
              the target network too.  Thus their IDS might report  5-10  port
              scans from unique IP addresses, but they won’t know which IP was
              scanning them and which were innocent decoys.  While this can be
              defeated  through  router  path  tracing, response-dropping, and
              other "active" mechanisms, it is generally an  extremely  effec-
              tive technique for hiding your IP address.

              Separate each decoy host with commas, and you can optionally use
              "ME" as one of the decoys to represent  the  position  you  want
              your IP address to be used.  If you put "ME" in the 6th position
              or later,  some  common  port  scan  detectors  (such  as  Solar
              Designer’s  excellent  scanlogd)  are  unlikely  to show your IP
              address at all.  If you don’t use "ME", nmap will put you  in  a
              random position.

              Note  that the hosts you use as decoys should be up or you might
              accidentally SYN flood your targets.  Also  it  will  be  pretty
              easy to determine which host is scanning if only one is actually
              up on the network.  You might want to use IP  addresses  instead
              of  names  (so  the  decoy networks don’t see you in their name-
              server logs).

              Also note that some "port  scan  detectors"  will  firewall/deny
              routing  to  hosts that attempt port scans.  The problem is that
              many scan types can be forged (as this option demonstrates).  So
              attackers  can  cause  such a machine to sever connectivity with
              important hosts such as its internet gateway, DNS  TLD  servers,
              sites  like  Windows  Update,  etc.   Most  such software offers
              whitelist capabilities, but you are unlikely to enumerate all of
              the  critical machines.  For this reason we never recommend tak-
              ing action against port scans that can be forged, including  SYN
              scans,  UDP  scans,  etc.  The machine you block could just be a
              decoy.

              Decoys are used both in the initial ping scan (using ICMP,  SYN,
              ACK,  or  whatever)  and  during the actual port scanning phase.
              Decoys are also used during remote OS detection ( <B>-O</B> ).

              It is worth noting that using too many decoys may slow your scan
              and  potentially  even  make  it less accurate.  Also, some ISPs
              will filter out your spoofed packets, although  many  (currently
              most) do not restrict spoofed IP packets at all.

       <B>-S</B> <B>&lt;IP_Address&gt;</B>
              In  some  circumstances,  <I>nmap</I> may not be able to determine your
              source address ( <I>nmap</I> will tell you if this is  the  case).   In
              this  situation,  use  -S with your IP address (of the interface
              you wish to send packets through).

              Another possible use of this flag is to spoof the scan  to  make
              the targets think that <B>someone</B> <B>else</B> is scanning them.  Imagine a
              company being repeatedly port scanned by a competitor!  This  is
              not  a  supported  usage  (or the main purpose) of this flag.  I
              just think it raises  an  interesting  possibility  that  people
              should  be aware of before they go accusing others of port scan-
              ning them.  <B>-e</B> would generally be  required  for  this  sort  of
              usage.

       <B>-e</B> <B>&lt;interface&gt;</B>
              Tells  nmap what interface to send and receive packets on.  Nmap
              should be able to detect this but it will tell you if it cannot.

       <B>--source_port</B> <B>&lt;portnumber&gt;</B>
              Sets  the source port number used in scans.  Many naive firewall
              and packet filter installations make an exception in their rule-
              set  to  allow DNS (53) or FTP-DATA (20) packets to come through
              and establish a connection.  Obviously this completely  subverts
              the security advantages of the firewall since intruders can just
              masquerade as FTP or DNS by modifying their source port.   Obvi-
              ously  for  a  UDP  scan  you  should try 53 first and TCP scans
              should try 20 before 53.  Note that this is only  a  request  --
              nmap will honor it only if and when it is able to.  For example,
              you can’t do TCP ISN sampling all  from  one  host:port  to  one
              host:port, so nmap changes the source port even if you used this
              option.  This is an alias for the shorter, but harder to  remem-
              ber, -g option.

              Be aware that there is a small performance penalty on some scans
              for using this option, because I sometimes store useful informa-
              tion in the source port number.

       <B>--data_length</B> <B>&lt;number&gt;</B>
              Normally  Nmap  sends  minimalistic  packets that only contain a
              header.  So its TCP packets are generally 40 bytes and ICMP echo
              requests  are  just  28.   This  option tells Nmap to append the
              given number of random bytes to most of the  packets  it  sends.
              OS detection (-O) packets are not affected, but most pinging and
              portscan packets are.   This  slows  things  down,  but  can  be
              slightly less conspicuous.

       <B>-n</B>     Tells  Nmap  to <B>NEVER</B> do reverse DNS resolution on the active IP
              addresses it finds.  Since DNS is  often  slow,  this  can  help
              speed things up.

       <B>-R</B>     Tells  Nmap to <B>ALWAYS</B> do reverse DNS resolution on the target IP
              addresses.  Normally this is only done when a machine  is  found
              to be alive.

       <B>-r</B>     Tells  Nmap  <B>NOT</B>  to  randomize  the  order  in  which ports are
              scanned.

       <B>--ttl</B> <B>&lt;value&gt;</B>
              Sets the IPv4 time to live field in sent packets  to  the  given
              value.

       <B>--randomize_hosts</B>
              Tells  Nmap  to shuffle each group of up to 2048 hosts before it
              scans them.  This can make the scans  less  obvious  to  various
              network  monitoring systems, especially when you combine it with
              slow timing options (see below).

       <B>-M</B> <B>&lt;max</B> <B>sockets&gt;</B>
              Sets the maximum number of sockets that will be used in parallel
              for  a TCP connect() scan (the default).  This is useful to slow
              down the scan a little bit and avoid crashing  remote  machines.
              Another  approach  is  to use -sS, which is generally easier for
              machines to handle.

       <B>--packet_trace</B>
              Tells Nmap to show all the packets it sends and  receives  in  a
              tcpdump-like format.  This can be tremendously useful for debug-
              ging, and is also a good learning tool.

       <B>--datadir</B> <B>[directoryname]</B>
              Nmap obtains some special data at runtime in files  named  nmap-
              service-probes,  nmap-services,  nmap-protocols, nmap-rpc, nmap-
              mac-prefixes, and  nmap-os-fingerprints.   Nmap  first  searches
              these files in the directory option to --datadir.  Any files not
              found there, are searched for in the directory specified by  the
              NMAPDIR environmental variable.  Next comes ~/.nmap for real and
              effective UIDs (POSIX systems only) or location of the Nmap exe-
              cutable  (Win32  only),  and then a compiled-in location such as
              /usr/local/share/nmap or /usr/share/nmap .  As  a  last  resort,
              Nmap will look in the current directory.

       <B>TIMING</B> <B>OPTIONS</B>
              Generally  Nmap does a good job at adjusting for Network charac-
              teristics at runtime and scanning as fast as possible while min-
              imizing  that chances of hosts/ports going undetected.  However,
              there are same cases where Nmap’s default timing policy may  not
              meet  your  objectives.   The  following  options provide a fine
              level of control over the scan timing:

       <B>-T</B> <B>&lt;Paranoid|Sneaky|Polite|Normal|Aggressive|Insane&gt;</B>
              These are canned timing  policies  for  conveniently  expressing
              your priorities to Nmap.  <B>Paranoid</B> mode scans <B>very</B> slowly in the
              hopes of avoiding detection by IDS systems.  It  serializes  all
              scans (no parallel scanning) and generally waits at least 5 min-
              utes between sending packets.  <B>Sneaky</B> is similar, except it only
              waits  15  seconds  between sending packets.  <B>Polite</B> is meant to
              ease load on the network and  reduce  the  chances  of  crashing
              machines.   It serializes the probes and waits <B>at</B> <B>least</B> 0.4 sec-
              onds between them.  Note that this  is  generally  at  least  an
              order  of  magnitude  slower  than default scans, so only use it
              when you need to.  <B>Normal</B> is the default  Nmap  behavior,  which
              tries to run as quickly as possible without overloading the net-
              work or missing hosts/ports.  <B>Aggressive</B> This  option  can  make
              certain  scans  (especially  SYN  scans against heavily filtered
              hosts) much faster.  It is recommended for impatient folks  with
              a  fast  net  connection.  <B>Insane</B> is only suitable for very fast
              networks or where you don’t mind losing  some  information.   It
              times  out hosts in 15 minutes and won’t wait more than 0.3 sec-
              onds for individual probes.  It does allow for very  quick  net-
              work sweeps though :).

              You  can  also  reference  these  by number (0-5).  For example,
              "-T0" gives you Paranoid mode and "-T5" is Insane mode.  If  you
              wish  to set specific timing values such as --max_rtt_timeout or
              --host_timeout, place them after any -T option  on  the  command
              line.   Otherwise the defaults for the selected timing mode will
              override your choices.

       <B>--host_timeout</B> <B>&lt;milliseconds&gt;</B>
              Specifies the amount of time Nmap is allowed to spend scanning a
              single  host  before  giving  up on that IP.  The default timing
              mode has no host timeout.

       <B>--max_rtt_timeout</B> <B>&lt;milliseconds&gt;</B>
              Specifies the maximum amount of time Nmap is allowed to wait for
              a  probe  response before retransmitting or timing out that par-
              ticular probe.  The default mode sets this to about 9000.

       <B>--min_rtt_timeout</B> <B>&lt;milliseconds&gt;</B>
              When the target hosts start to establish a pattern of responding
              very  quickly,  Nmap  will  shrink  the amount of time given per
              probe.  This speeds up the scan, but can lead to missed  packets
              when  a  response  takes longer than usual.  With this parameter
              you can guarantee that Nmap will wait at least the given  amount
              of time before giving up on a probe.

       <B>--initial_rtt_timeout</B> <B>&lt;milliseconds&gt;</B>
              Specifies  the  initial  probe  timeout.  This is generally only
              useful when scanning firewalled hosts with -P0.   Normally  Nmap
              can  obtain  good  RTT estimates from the ping and the first few
              probes.  The default mode uses 6000.

       <B>--max_hostgroup</B> <B>&lt;numhosts&gt;</B>
              Specifies the maximum number of hosts that Nmap  is  allowed  to
              scan  in  parallel.   Most  of  the port scan techniques support
              multi-host operation, which makes them much quicker.   Spreading
              the  load  among  multiple target hosts makes the scans gentler.
              The downside is increast results latency.  You need to wait  for
              all  hosts  in a group to finish, rather than having them pop up
              one by one.  Specify an argument of one for old-style (one  host
              at  a  time)  Nmap behavior.  Note that the ping scanner handles
              its own grouping, and ignores this value.

       <B>--min_hostgroup</B> <B>&lt;milliseconds&gt;</B>
              Specifies the minimum host  group  size  (see  previous  entry).
              Large  values  (such  as 50) are often beneficial for unattended
              scans, though they do take up more memory.   Nmap  may  override
              this  preference  when it needs to, because a group must all use
              the same network interface, and some scan types can only  handle
              one host at a time.

       <B>--max_parallelism</B> <B>&lt;number&gt;</B>
              Specifies the maximum number of scans Nmap is allowed to perform
              in parallel.  Setting this to one means Nmap will never  try  to
              scan more than 1 port at a time.  It also effects other parallel
              scans such as ping sweep, RPC scan, etc.

       <B>--min_parallelism</B> <B>&lt;number&gt;</B>
              Tells Nmap to scan at least the given number of ports in  paral-
              lel.   This  can speed up scans against certain firewalled hosts
              by an order of magnitude.  But be careful -- results will become
              unreliable if you push it too far.

       <B>--scan_delay</B> <B>&lt;milliseconds&gt;</B>
              Specifies  the  <B>minimum</B>  amount  of  time Nmap must wait between
              probes.  This is mostly useful to reduce network load or to slow
              the  scan  way  down  to  sneak under IDS thresholds.  Nmap will
              sometimes increase the delay itself when it detects many dropped
              packets.  For example, Solaris systems tend to respond with only
              one ICMP port unreachable packet per second during a  UDP  scan.
              So Nmap will try to detect this and lower its rate of UDP probes
              to one per second.

       <B>--max_scan_delay</B> <B>&lt;milliseconds&gt;</B>
              As noted above, Nmap will  sometimes  enforce  a  special  delay
              between sending packets.  This can provide more accurate results
              while reducing network congestion, but it  can  slow  the  scans
              down  substantially.  By default (with no -T options specified),
              Nmap allows this delay to grow to one second  per  probe.   This
              option allows you to set a lower or higher maximum.  Even if you
              set it to zero, Nmap will have some delay between  packet  sends
              so  that  it  can  wait  for responses and avoid having too many
              outstanding probes in parallel.



</PRE>
<H2>TARGET SPECIFICATION</H2><PRE>
       Everything that isn’t an option (or option argument) in nmap is treated
       as  a  target  host specification.  The simplest case is listing single
       hostnames or IP addresses on the command line.  If you want to  scan  a
       subnet  of  IP  addresses,  you  can append <B>/mask</B> to the hostname or IP
       address.  <B>mask</B> must be between 0 (scan the whole Internet) and 32 (scan
       the  single  host  specified).  Use /24 to scan a class "C" address and
       /16 for a class "B".

       Nmap also has a more powerful notation which lets  you  specify  an  IP
       address  using  lists/ranges  for  each element.  Thus you can scan the
       whole class "B" network  192.168.*.*  by  specifying  "192.168.*.*"  or
       "192.168.0-255.0-255" or even "192.168.1-50,51-255.1,2,3,4,5-255".  And
       of course you can use the mask notation: "192.168.0.0/16".   These  are
       all  equivalent.  If you use asterisks ("*"), remember that most shells
       require you to escape them with  back  slashes  or  protect  them  with
       quotes.

       Another  interesting  thing  to do is slice the Internet the other way.
       Instead of scanning all the hosts in a class "B", scan  "*.*.5.6-7"  to
       scan  every IP address that ends in .5.6 or .5.7 Pick your own numbers.
       For more information on specifying hosts to scan, see the <I>examples</I> sec-
       tion.


</PRE>
<H2>EXAMPLES</H2><PRE>
       Here  are some examples of using nmap, from simple and normal to a lit-
       tle more complex/esoteric.  Note that actual numbers  and  some  actual
       domain names are used to make things more concrete.  In their place you
       should substitute addresses/names from <B>your</B>  <B>own</B>  <B>network.</B>   I  do  not
       think  portscanning  other networks is illegal; nor should portscans be
       construed by others as an attack.  I have scanned hundreds of thousands
       of  machines  and  have  received  only  one complaint.  But I am not a
       lawyer and some (anal) people may be annoyed by <I>nmap</I> probes.  Get  per-
       mission first or use at your own risk.

       <B>nmap</B> <B>-v</B> <B>target.example.com</B>

       This  option  scans  all reserved TCP ports on the machine target.exam-
       ple.com .  The -v means turn on verbose mode.

       <B>nmap</B> <B>-sS</B> <B>-O</B> <B>target.example.com/24</B>

       Launches a stealth SYN scan against each machine that is up out of  the
       255  machines  on  class "C" where target.example.com resides.  It also
       tries to determine what operating system is running on each  host  that
       is  up  and  running.  This requires root privileges because of the SYN
       scan and the OS detection.

       <B>nmap</B> <B>-sX</B> <B>-p</B> <B>22,53,110,143,4564</B> <B>198.116.*.1-127</B>

       Sends an Xmas tree scan to the first half of each of the 255 possible 8
       bit  subnets  in  the  198.116 class "B" address space.  We are testing
       whether the systems run sshd, DNS, pop3d, imapd, or  port  4564.   Note
       that  Xmas  scan doesn’t work on Microsoft boxes due to their deficient
       TCP stack.  Same goes with CISCO, IRIX, HP/UX, and BSDI boxes.

       <B>nmap</B> <B>-v</B> <B>--randomize_hosts</B> <B>-p</B> <B>80</B> <B>*.*.2.3-5</B>

       Rather than focus on a specific IP range, it is  sometimes  interesting
       to  slice  up  the  entire  Internet  and scan a small sample from each
       slice.  This  command  finds  all  web  servers  on  machines  with  IP
       addresses  ending in .2.3, .2.4, or .2.5.  If you are root you might as
       well add -sS.  Also you will find more interesting machines starting at
       127.  so you might want to use "127-222" instead of the first asterisks
       because that section has a  greater  density  of  interesting  machines
       (IMHO).

       <B>host</B> <B>-l</B> <B>company.com</B> <B>|</B> <B>cut</B>  <B>-d</B>  <B>-f</B> <B>4</B> <B>|</B> <B>./nmap</B> <B>-v</B> <B>-iL</B> <B>-</B>

       Do  a  DNS zone transfer to find the hosts in company.com and then feed
       the IP addresses to <I>nmap.</I>  The above commands are for my GNU/Linux box.
       You may need different commands/options on other operating systems.


</PRE>
<H2>BUGS</H2><PRE>
       Bugs?   What bugs?  Send me any that you find.  Patches are nice too :)
       Remember to also send in  new  OS  fingerprints  so  we  can  grow  the
       database.  Nmap will give you a submission URL when an appropriate fin-
       gerprint is found.


</PRE>
<H2>AUTHOR</H2><PRE>
       Fyodor <I>&lt;fyodor@insecure.org&gt;</I>


</PRE>
<H2>DISTRIBUTION</H2><PRE>
       The newest version  of  <I>nmap</I>  can  be  obtained  from  <I>http://www.inse-</I>
       <I>cure.org/nmap/</I>

       The  Nmap  Security  Scanner is (C) 1996-2004 Insecure.Com LLC. Nmap is
       also a registered trademark of Insecure.Com LLC.  This program is  free
       software;  you may redistribute and/or modify it under the terms of the
       GNU General Public License as published by the  Free  Software  Founda-
       tion; Version 2.  This guarantees your right to use, modify, and redis-
       tribute this software under certain conditions.  If you wish  to  embed
       Nmap  technology  into  proprietary software, we may be willing to sell
       alternative licenses (contact sales@insecure.com).  Many security scan-
       ner  vendors already license Nmap technology such as our remote OS fin-
       gerprinting database and code, service/version  detection  system,  and
       port scanning code.

       Note that the GPL places important restrictions on "derived works", yet
       it does not provide a detailed definition of that term.  To avoid  mis-
       understandings,  we consider an application to constitute a "derivative
       work" for the purpose of this license if it does any of the following:

       o Integrates source code from Nmap

       o Reads or includes Nmap copyrighted data files, such  as  nmap-os-fin-
       gerprints or nmap-service-probes.

       o  Executes Nmap and parses the results (as opposed to typical shell or
       execution-menu apps, which simply display raw Nmap output  and  so  are
       not derivative works.)

       o  Integrates/includes/aggregates  Nmap  into  a proprietary executable
       installer, such as those produced by InstallShield.

       o Links to a library or executes a program that does any of the above

       The term "Nmap" should be taken to also include any portions or derived
       works  of Nmap.  This list is not exclusive, but is just meant to clar-
       ify our interpretation of derived  works  with  some  common  examples.
       These restrictions only apply when you actually redistribute Nmap.  For
       example, nothing stops you  from  writing  and  selling  a  proprietary
       front-end  to  Nmap.  Just distribute it by itself, and point people to
       http://www.insecure.org/nmap/ to download Nmap.

       We don’t consider these to be added restrictions on top of the GPL, but
       just  a clarification of how we interpret "derived works" as it applies
       to our GPL-licensed Nmap product.  This is similar  to  the  way  Linus
       Torvalds  has  announced  his  interpretation  of  how  "derived works"
       applies to Linux kernel modules.  Our  interpretation  refers  only  to
       Nmap - we don’t speak for any other GPL products.

       If you have any questions about the GPL licensing restrictions on using
       Nmap in non-GPL works, we would be happy to help.  As mentioned  above,
       we  also  offer  alternative license to integrate Nmap into proprietary
       applications and appliances.  These contracts have been  sold  to  many
       security  vendors, and generally include a perpetual license as well as
       providing for priority support and updates as well as helping  to  fund
       the   continued   development   of   Nmap   technology.   Please  email
       sales@insecure.com for further information.

       As a special exception to the GPL terms, Insecure.Com LLC  grants  per-
       mission  to  link  the  code  of  this  program with any version of the
       OpenSSL library which is distributed under a license identical to  that
       listed in the included Copying.OpenSSL file, and distribute linked com-
       binations including the two. You must obey the GNU GPL in all  respects
       for  all of the code used other than OpenSSL.  If you modify this file,
       you may extend this exception to your version of the file, but you  are
       not obligated to do so.

       If  you  received  these files with a written license agreement or con-
       tract stating terms other than the terms above, then  that  alternative
       license agreement takes precedence over these comments.

       Source  is  provided  to  this software because we believe users have a
       right to know exactly what a program is going to do before they run it.
       This  also  allows  you  to audit the software for security holes (none
       have been found so far).

       Source code also allows you to port Nmap to new  platforms,  fix  bugs,
       and  add  new features.  You are highly encouraged to send your changes
       to fyodor@insecure.org for possible incorporation into the main distri-
       bution.   By  sending  these  changes to Fyodor or one the Insecure.Org
       development mailing lists, it is assumed that you are  offering  Fyodor
       and  Insecure.Com LLC the unlimited, non-exclusive right to reuse, mod-
       ify, and relicense the  code.   Nmap  will  always  be  available  Open
       Source,  but  this is important because the inability to relicense code
       has caused devastating problems for other Free Software projects  (such
       as  KDE  and  NASM).   We also occasionally relicense the code to third
       parties as discussed above.  If you wish  to  specify  special  license
       conditions of your contributions, just say so when you send them.

       This  program  is  distributed  in the hope that it will be useful, but
       WITHOUT ANY  WARRANTY;  without  even  the  implied  warranty  of  MER-
       CHANTABILITY  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
       Public License for more details at http://www.gnu.org/copyleft/gpl.html
       , or in the COPYING file included with Nmap.

       It  should  also  be  noted  that  Nmap has been known to crash certain
       poorly written applications, TCP/IP stacks, and even operating systems.
       <B>Nmap</B>  <B>should</B>  <B>never</B>  <B>be</B> <B>run</B> <B>against</B> <B>mission</B> <B>critical</B> <B>systems</B> unless you
       are prepared to suffer downtime.  We acknowledge  here  that  Nmap  may
       crash  your  systems  or networks and we disclaim all liability for any
       damage or problems Nmap could cause.

       Because of the slight risk of crashes and because a few black hats like
       to  use  Nmap  for reconnaissance prior to attacking systems, there are
       administrators who become upset and may complain when their  system  is
       scanned.   Thus,  it  is  often  advisable to request permission before
       doing even a light scan of a network.

       Nmap should never be installed with special privileges (eg  suid  root)
       for security reasons.

       This product includes software developed by the Apache Software Founda-
       tion (http://www.apache.org/).  The  <I>Libpcap</I>  portable  packet  capture
       library  is  distributed along with nmap.  Libpcap was originally copy-
       righted by Van Jacobson, Craig Leres and Steven  McCanne,  all  of  the
       Lawrence Berkeley National Laboratory, University of California, Berke-
       ley, CA.  It is now maintained by http://www.tcpdump.org .

       Regular expression support is provided by  the  PCRE  library  package,
       which  is  open source software, written by Philip Hazel, and copyright
       by the University of Cambridge, England.  See http://www.pcre.org/ .

       Nmap can optionally link to the OpenSSL cryptography toolkit, which  is
       available from http://www.openssl.org/ .

       US  Export  Control: Insecure.Com LLC believes that Nmap falls under US
       ECCN (export control classification number) 5D992.   This  category  is
       called  ’"Information  Security"  "software"  not controlled by 5D002’.
       The only restriction of this  classification  is  AT  (anti-terrorism),
       which  applies  to  almost  all goods and denies export to a handful of
       rogue nations such as Iran and North Korea.  Thus exporting  Nmap  does
       not  require  any special license, permit, or other governmental autho-
       rization.



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