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NETMASK(1)			 Debian	Linux			    NETMASK(1)

NAME
       netmask - a netmask generation and conversion program

SYNOPSIS
       netmask [ options ] spec	[ spec ... ]

DESCRIPTION
       This  program  accepts and produces a variety of	common network address
       and netmask formats.  Not only can it convert address and netmask nota-
       tions, but it will optimize the masks to	generate the smallest list  of
       rules.	This  is  very	handy  if you've ever configured a firewall or
       router and some nasty network administrator  before  you	 decided  that
       base 10 numbers were good places	to start and end groups	of machines.

OPTIONS
       -h, --help
	      Print a summary of the options

       -v, --version
	      Print the	version	number

       -d, --debug
	      Print status/progress information

       -s, --standard
	      Output address/netmask pairs

       -c, --cidr
	      Output CIDR format address lists

       -i, --cisco
	      Output Cisco style address lists

       -r, --range
	      Output ip	address	ranges

       -x, --hex
	      Output address/netmask pairs in hex

       -o, --octal
	      Output address/netmask pairs in octal

       -b, --binary
	      Output address/netmask pairs in binary

       -n, --nodns
	      Disable DNS lookups for addresses

DEFINITIONS
       A spec is an address specification, it can look like:

       address
	      One address.

       address1:address2
	      All addresses from address1 to address2.

       address1:+address2
	      All addresses from address1 to address1+address2.

       address/mask
	      A	group starting at address spanning mask.

       An address is an	internet network address, it can look like:

       ftp.gnu.org
	      An internet hostname.

       209.81.8.252
	      A	standard dotted	quad internet address notation.

       100    A	decimal	number (100 in this case).

       0100   An octal number preceded by "0" (64 in this case).

       0x100  A	hexadecimal number preceded by "0x" (256 in this case).

       A mask is a network mask, it can	look like:

       255.255.224.0
	      A	 dotted	 quad  netmask	(netmask  will complain	if it is not a
	      valid netmask).

       0.0.31.255
	      A	Cisco style inverse netmask (preceded by a tilde  (~)  charac-
	      ter).

       8      The number of bits set to	one from the left (CIDR	notation).

       010    The number of bits set to	one from the left in octal.

       0x10   The number of bits set to	one from the left in hexadecimal.

AUTHOR
       netmask	was  written by	Robert Stone.  Some algorithm design and opti-
       mization	was provided by	Tom Lear.  This	manual	page  was  written  by
       Robert Stone.

BUGS
       Let  me	know  if you find any.	This man page is a bit more simplistic
       than I'd	like, but I've forgotten most of the groff I once knew.

SEE ALSO
       ipchains(1), ipfwadm(8),	 netstat(8),  route(8),	 routed(8),  gated(8),
       tcpd(8)

Debian Project			  15 May 1999			    NETMASK(1)

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