Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
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 sup-
       port 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
       implementations 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 nobody knows why...).

       To use Whatmask in the first mode simply	type "whatmask <notation>" The
       notation	 can be	in any of the four formats and Whatmask	will automagi-
       cally 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),
       Wildcard	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  ad-
	      dress 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 feed-
       back!

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

LAFFEY Computer	Imaging		 Nov 14, 2003			   Whatmask(1)

NAME | SYNTAX | DESCRIPTION | OPTIONS | EXAMPLES | BUGS | CONTRIBUTORS | UPDATES

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=whatmask&sektion=1&manpath=FreeBSD+13.0-RELEASE+and+Ports>

home | help