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Man Pages


Manual Reference Pages  -  NETMASK (1)

NAME

netmask - a netmask generation and conversion program

CONTENTS

Synopsis
Description
Options
Definitions
Author
Bugs
See Also

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 notations, 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 (~) character).
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 optimization 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)
Search for    or go to Top of page |  Section 1 |  Main Index


Debian Project NETMASK (1) 15 May 1999

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