为什么192.168.0.0不能分配给设备？

Question

192.168.0.0可以是网络地址，不能分配给本地网络中的任何设备。但是为什么呢？路由器不能使用掩码(比如255.255.0.0)，知道网络地址是什么吗？

Answer 1

来自http://web.archive.org/web/20100821112028/http://www.3com.com/other/pdfs/infra/corpinfo/en_US/501302.pdf (第14页)：

根据互联网惯例为每个子网定义主机地址，IP地址的主机号字段不能包含所有0位或所有1位。所有0位主机号码标识基本网络(或子网络)号码，而all-1s主机号表示网络(或子网)的广播地址。

更权威的是http://www.ietf.org/rfc/rfc943.txt的RFC-943：

In certain contexts, it is useful to have fixed addresses with
functional significance rather than as identifiers of specific
hosts.  When such usage is called for, the address zero is to be
interpreted as meaning "this", as in "this network".  The address
of all ones are to be interpreted as meaning "all", as in "all
hosts".  For example, the address 128.9.255.255 could be
interpreted as meaning all hosts on the network 128.9.  Or, the
address 0.0.0.37 could be interpreted as meaning host 37 on this
network.