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Full Discussion: Subnetting
Special Forums IP Networking Subnetting Post 302993569 by lobsang on Saturday 11th of March 2017 07:33:30 AM
Old 03-11-2017
Quote:
Originally Posted by drysdalk
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.
Thank you Drysdalk . i believe i didn't understood properly what a single ip address means. From your above explanation . for e.g.
Code:
192.168.1.1 through 192.168.1.254 - Free IPs (Usable for hosts)

Does all those ip are list of single ip address. i believe list of hosts in ip class means list of single ip address. Does my public ip address as mentioned
Code:
46.126.40.51

means one of hosts from class A public ip address .
 

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WHOIS(1)						    BSD General Commands Manual 						  WHOIS(1)

NAME
whois -- Internet domain name and network number directory service SYNOPSIS
whois [-6AadfgilmQRr] [-c country-code | -h host] [-p port] name [...] DESCRIPTION
The whois utility looks up records in the databases maintained by several Network Information Centers (NICs). The options are as follows: -6 Use the IPv6 Resource Center (6bone) database. It contains network names and addresses for the IPv6 network. -A Use the Asia/Pacific Network Information Center (APNIC) database. It contains network numbers used in East Asia, Australia, New Zea- land, and the Pacific islands. -a Use the American Registry for Internet Numbers (ARIN) database. It contains network numbers used in those parts of the world not covered by AfriNIC, APNIC, LACNIC or by RIPE. (Hint: All point of contact handles in the ARIN whois database end with "-ARIN".) -c country-code This is the equivalent of using the -h option with an argument of "country-code.whois-servers.net". -d Use the US Department of Defense database. It contains points of contact for subdomains of .MIL. -f Use the African Network Information Center (AfriNIC) database. It contains network numbers used in Africa. -g Use the US non-military federal government database, which contains points of contact for subdomains of .GOV. -h host Use the specified host instead of the default NIC (whois.crsnic.net). Either a host name or an IP address may be specified. By default whois constructs the name of a whois server to use from the top-level domain (TLD) of the supplied (single) argument, and appending ".whois-servers.net". This effectively allows a suitable whois server to be selected automatically for a large number of TLDs. In the event that an IP address is specified, the whois server will default to the American Registry for Internet Numbers (ARIN). If a query to ARIN references AfriNIC, APNIC, LACNIC, or RIPE, that server will be queried also, provided that the -Q option is not specified. If the query is not a domain name or IP address, whois will fall back to whois.crsnic.net. -i Use the Network Solutions Registry for Internet Numbers (whois.networksolutions.com) database. Historically, it contained network numbers and domain contact information for most of .COM, .NET, .ORG and .EDU domains. However, the registration of these domains is now done by a number of independent and competing registrars and this database holds no information on the domains registered by organizations other than Network Solutions, Inc. Also, note that the InterNIC database (whois.internic.net) is no longer handled by Network Solutions, Inc. For details, see http://www.internic.net/. (Hint: Contact information, identified by the term handle, can be looked up by prefixing "!" or "handle " to the NIC handle in the query.) -l Use the Latin American and Caribbean IP address Regional Registry (LACNIC) database. It contains network numbers used in much of Latin America and the Caribbean. -m Use the Route Arbiter Database (RADB) database. It contains route policy specifications for a large number of operators' networks. -p port Connect to the whois server on port. If this option is not specified, whois defaults to the ``whois'' port listed in /etc/services (port 43). -Q Do a quick lookup. This means that whois will not attempt to lookup the name in the authoritative whois server (if one is listed) nor will it contact InterNic if a lookup fails. This flag has no effect when combined with any other flag. -R Use the Russia Network Information Center (RIPN) database. It contains network numbers and domain contact information for subdomains of .RU. This option is deprecated; use the -c option with an argument of "RU" instead. -r Use the R'eseaux IP Europ'eens (RIPE) database. It contains network numbers and domain contact information for Europe. The default action, unless directed otherwise with a special name, is to do a very broad search, looking for matches to name in all types of records and most fields (name, nicknames, hostname, net address, etc.) in the database. For more information as to what name operands have special meaning, and how to guide the search, use the special name ``help''. Special cases Queries beginning with an exclamation point '!' are assumed to be NSI contact handles. Unless a host or domain is specified on the command line, (whois.networksolutions.com) will be used as the whois database. Similarly, queries beginning with ``COCO-'' are assumed to be CORE contact handles. Unless a host or domain is specified on the command line, (whois.corenic.net) will be used as the whois database. EXAMPLES
Most types of data, such as domain names and IP addresses, can be used as arguments to whois without any options, and whois will choose the correct whois server to query. Some exceptions, where whois will not be able to handle data correctly, are detailed below. To obtain contact information about an administrator located in the Russian TLD domain "RU", use the -c option as shown in the following example, where CONTACT-ID is substituted with the actual contact identifier. whois -c RU CONTACT-ID (Note: This example is specific to the TLD "RU", but other TLDs can be queried by using a similar syntax.) The following example demonstrates how to obtain information about an IPv6 address or hostname using the -6 option, which directs the query to 6bone. whois -6 IPv6-IP-Address The following example demonstrates how to query a whois server using a non-standard port, where ``query-data'' is the query to be sent to ``whois.example.com'' on port ``rwhois'' (written numerically as 4321). whois -h whois.example.com -p rwhois query-data SEE ALSO
Ken Harrenstien and Vic White, NICNAME/WHOIS, 1 March 1982, RFC 812. HISTORY
The whois command appeared in 4.3BSD. BSD
September 9, 2007 BSD
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