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Whatmask(1)			     Network			     Whatmask(1)

NAME
     whatmask - Subnet mask notation conversion tool.

SYNTAX
     whatmask <netmask or ip/netmask>
     see the Examples section below

DESCRIPTION
     Whatmask is a small C program that will help you with network settings.

     Whatmask  can work in two modes.  The first mode is to invoke Whatmask with
     only a subnet mask as the argument. In this mode Whatmask	will  echo  back
     the  subnet  mask	in four formats, plus the number of useable addresses in
     the range.

     Netmask Notations supported:
      Name		    Example

      CIDR			   /24
      Netmask		 255.255.255.0
      Netmask (hex)	    0xffffff00
      Wilcard Bits	     0.0.0.255

     The above notations are all identical.  CIDR notation commonly has a "/" in
     front of the number (representing the number of bits).  Whatmask can accept
     these notations with or without a slash. This notation  is  used  more  and
     more recently. A lot of popular routers and software support this notation.

     Netmask notation is pretty much the standard old-school way of doing it. It
     is supported by most systems (Un*x, Win, Mac, etc.).

     Netmask (Hex) is the hexadecimal representation of the netmask. Many imple-
     mentations of ifconfig use this notation

     Wilcard  Bits  are  similar to the netmask, but they are the logical not of
     the netmask. This notation is used by a number of popular routers (and  no-
     body knows why...).

     To use Whatmask in the first mode simply type "whatmask <notation>" The no-
     tation  can  be  in any of the four formats and Whatmask will automagically
     figure out what it is and display all four notations.

     To use Whatmask in its second mode execute Whatmask  with	any  ip  address
     within  the  subnet, followed by a slash ('/'), followed by the subnet mask
     in any format. (e.g. 192.168.0.23/255.255.255.224, or 192.168.0.23/27)  Put
     no spaces in the argument.

     Whatmask will echo back the following:

     - The netmask in the following formats: CIDR, Netmask, Netmask (Hex), Wild-
     card Bits

     - The Network Address

     - The Broadcast Address

     - The number of Usable IP Addresses

     - The First Usable IP Address

     - The Last Usable IP Address

	    (Whatmask  assumes that the Broadcast address is the highest address
	    in the subnet. This is the most common configuration.)

OPTIONS
     <no options> see above and below for usage.

EXAMPLES
     Examples of how Whatmask works:

	  myhost> whatmask /26

	  ---------------------------------------------
		  TCP/IP SUBNET MASK EQUIVALENTS
	  ---------------------------------------------
	  CIDR = .....................: /26
	  Netmask = ..................: 255.255.255.192
	  Netmask (hex) = ............: 0xffffffc0
	  Wildcard Bits = ............: 0.0.0.63
	  Usable IP Addresses = ......: 62

	  myhost> whatmask 255.255.192.0

	  ---------------------------------------------
		  TCP/IP SUBNET MASK EQUIVALENTS
	  ---------------------------------------------
	  CIDR = .....................: /18
	  Netmask = ..................: 255.255.192.0
	  Netmask (hex) = ............: 0xffffc000
	  Wildcard Bits = ............: 0.0.63.255
	  Usable IP Addresses = ......: 16,382

	  myhost> whatmask 0xffffffe0

	  ---------------------------------------------
		  TCP/IP SUBNET MASK EQUIVALENTS
	  ---------------------------------------------
	  CIDR = .....................: /27
	  Netmask = ..................: 255.255.255.224
	  Netmask (hex) = ............: 0xffffffe0
	  Wildcard Bits = ............: 0.0.0.31
	  Usable IP Addresses = ......: 30

	  myhost> whatmask 0.0.0.31

	  ---------------------------------------------
		  TCP/IP SUBNET MASK EQUIVALENTS
	  ---------------------------------------------
	  CIDR = .....................: /27
	  Netmask = ..................: 255.255.255.224
	  Netmask (hex) = ............: 0xffffffe0
	  Wildcard Bits = ............: 0.0.0.31
	  Usable IP Addresses = ......: 30

	  myhost> whatmask 192.168.165.23/19

	  ------------------------------------------------
		       TCP/IP NETWORK INFORMATION
	  ------------------------------------------------
	  IP Entered = ..................: 192.168.165.23
	  CIDR = ........................: /19
	  Netmask = .....................: 255.255.224.0
	  Netmask (hex) = ...............: 0xffffe000
	  Wildcard Bits = ...............: 0.0.31.255
	  ------------------------------------------------
	  Network Address = .............: 192.168.160.0
	  Broadcast Address = ...........: 192.168.191.255
	  Usable IP Addresses = .........: 8,190
	  First Usable IP Address = .....: 192.168.160.1
	  Last Usable IP Address = ......: 192.168.191.254

	  myhost> whatmask 192.168.0.13/255.255.255.0

	  ------------------------------------------------
		       TCP/IP NETWORK INFORMATION
	  ------------------------------------------------
	  IP Entered = ..................: 192.168.0.13
	  CIDR = ........................: /24
	  Netmask = .....................: 255.255.255.0
	  Netmask (hex) = ...............: 0xffffff00
	  Wildcard Bits = ...............: 0.0.0.255
	  ------------------------------------------------
	  Network Address = .............: 192.168.0.0
	  Broadcast Address = ...........: 192.168.0.255
	  Usable IP Addresses = .........: 254
	  First Usable IP Address = .....: 192.168.0.1
	  Last Usable IP Address = ......: 192.168.0.254

	  myhost> whatmask 192.168.0.113/0xffffffe0

	  ------------------------------------------------
		       TCP/IP NETWORK INFORMATION
	  ------------------------------------------------
	  IP Entered = ..................: 192.168.0.113
	  CIDR = ........................: /27
	  Netmask = .....................: 255.255.255.224
	  Netmask (hex) = ...............: 0xffffffe0
	  Wildcard Bits = ...............: 0.0.0.31
	  ------------------------------------------------
	  Network Address = .............: 192.168.0.96
	  Broadcast Address = ...........: 192.168.0.127
	  Usable IP Addresses = .........: 30
	  First Usable IP Address = .....: 192.168.0.97
	  Last Usable IP Address = ......: 192.168.0.126

	  myhost> whatmask 192.168.0.169/0.0.0.127

	  ------------------------------------------------
		       TCP/IP NETWORK INFORMATION
	  ------------------------------------------------
	  IP Entered = ..................: 192.168.0.169
	  CIDR = ........................: /25
	  Netmask = .....................: 255.255.255.128
	  Netmask (hex) = ...............: 0xffffff80
	  Wildcard Bits = ...............: 0.0.0.127
	  ------------------------------------------------
	  Network Address = .............: 192.168.0.128
	  Broadcast Address = ...........: 192.168.0.255
	  Usable IP Addresses = .........: 126
	  First Usable IP Address = .....: 192.168.0.129
	  Last Usable IP Address = ......: 192.168.0.254

BUGS
     Report bugs to <software@laffeycomputer.com>

CONTRIBUTORS
     Original code:
	    Joe Laffey <software@laffeycomputer.com>

     Assistance with Manpage and Packaging:
	    David Wirch <kuma@linuxboxen.org>

     Many thanks to the beta testers and users who sent in valuable feedback!

UPDATES
     Official Whatmask website:
	    http://www.laffeycomputer.com/whatmask.html

LAFFEY Computer Imaging 	  Nov 14, 2003			     Whatmask(1)
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