03-11-2017
Hi,
To put it as simply as possible, in any given network range the very first address and the very last address are not usable for hosts. The first address is the network address, and the last address is the broadcast address.
So for 192.168.1.0/24 you'd have:
192.168.1.0 - Network address (NOT usable for hosts)
192.168.1.1 through 192.168.1.254 - Free IPs (Usable for hosts)
192.168.1.255 - Broadcast address (NOT usable for hosts)
And for /25 sub-nets (and all others besides) it'd be the same: the first address in the range and the last address in the range are not usable for hosts.
These 2 Users Gave Thanks to drysdalk For This Post:
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LEARN ABOUT OPENSOLARIS
whois
whois(1) User Commands whois(1)
NAME
whois - Internet user name directory service
SYNOPSIS
whois [-h host] identifier
DESCRIPTION
whois searches for an Internet directory entry for an identifier which is either a name (such as ``Smith'') or a handle (such as ``SRI-
NIC''). To force a name-only search, precede the name with a period; to force a handle-only search, precede the handle with an exclamation
point.
To search for a group or organization entry, precede the argument with * (an asterisk). The entire membership list of the group will be
displayed with the record.
You may of course use an exclamation point and asterisk, or a period and asterisk together.
EXAMPLES
Example 1 Using The whois Command
The command:
example% whois Smith
looks for the name or handle SMITH.
The command:
example% whois !SRI-NIC
looks for the handle SRI-NIC only.
The command:
example% whois .Smith, John
looks for the name JOHN SMITH only.
Adding ... to the name or handle argument will match anything from that point; that is, ZU ... will match ZUL, ZUM, and so on.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWrcmdc |
+-----------------------------+-----------------------------+
SEE ALSO
attributes(5)
SunOS 5.11 6 Nov 2000 whois(1)