ngen - create a baseline set of nmap results from command-line specifications and/or an nmap results file.

 ngen [-o|-output <filename-or-:tag>] [-p|-ports <port list>] 
      [-h|-host <specification> ... -h|-host <specification N>]

      <specification> = 
      [!]<host spec>[:<port spec>][:ignored state]

The ngen utility creates an nmap-style machine-readable results file for use as a baseline for ndiff comparision.

-o <filename-or-:tag>

-output <filename-or-:tag>

Specifies the output filename, or optionally a data store tag, if begins with a colon (:). See DATA STORES below for more information.

-p <port list>

-ports <port list>

Specifies the set of all ports scanned, comma-separated. Ranges may be specified. For example:

    -p 80,443,6000-6010,22
    -ports 53

By default, tcp is assumed; udp may be specified by appending the u flag. (t may be specified but is redundant)

    -p 323u,80,6000-6010t

If the -p option is omitted, ngen will grab the set of ports from /usr/local/lib/nmap/nmap-services and /etc/services. The default, Ignored specified for a given host is applied to all ports in this list, except for interesting ports, which are specified below with the -h option. See the description of port specifications with the -h option below for more information.

-h [!]<host ranges>[:<port ranges>][:<ignored state>]

-host [!]<host ranges>[:<port ranges>][:<ignored state>]

Adds a host or range of hosts. For example

    -h 192.168.2.2                   # one host
    -h 10.0.2.0-64                   # 65 hosts
    -host 192.168.1.0/26             # 64 hosts
    -host 192.168.*.*                # 65536 hosts

The above examples add hosts with all ports closed. To add ports to the hosts, append a colon and a port spec. For example to add localhost with tcp ports 80 and 53 open, ignored state closed, the specification would be

    -host 127.0.0.1:80,53

Flags may be appended to change the protocol or state for a given port, for example:

    -host 127.0.0.1:7uf

which adds echo service, udp port 7 filtered state. The full list of port flags are as follows:

    t - tcp port  (default)
    u - udp port

    o - port is in open state (default)
    c - port is in closed state 
    f - port is in filtered state
    x - port is in unfiltered state

The ignored state for the host may be specified by appending a colon and the state to the host spec. Acceptable state labels are open, closed, filtered, and unfiltered.

  -h 10.0.2.0:80f:closed

which says all scanned ports default to closed state, except for 80/tcp which is filtered. A host spec is treated as a negation if it starts with !. If ports are specified as part of the host spec, those ports are deleted from any hosts previously added which fall in the host range. Host specs are applied in order as they appear on the command line, and their effects are cumulative.

Nrun and its related tools can manipulate results in regular nmap-format files, in any user-specified location, or they can handle storing and organizing the data on behalf of the user, through a user-configurable data store.

Whenever you precede a results tag with a colon (:), the tag will be treated as a unique key into a data store, identifying the results set.

Currently the only supported data store is nmap format files placed in a preconfigured directory. Other types may be added at a later date.

A legal tag may contain any alphanumeric string, plus dash, underscore, and dot. %-style substitutions in the ilk of the date command are also supported, allowing a tag to contain date, time, or the local hostname. See SUBSTITUTIONS below for more information.

%-style substitutions supported in tags as follows:

%H = hour

%M = minute

%S = second

%D = day of month

%m = month of year (01-12)

%Y = year, four digits

%j = day of year, three digits

%w = day of week (0-6) one digit

Except where noted, the above items are two digits, and local time. All are zero-padded as appropriate.

In addtion-

It is possible to create invalid nmap result files with ngen if you really try to. No support for human-readable hostnames and portnames.

James Levine <jdl@vinecorp.com>