ccna 200-301 network simulator tools internet option

ccna 200-301 network simulator tools internet option.packets to a broadcast IP address are received by all hosts on the network. For example, in the default Class C network 192.168.1.0, the IP addresses range from 192.168.1.0 to 192.168.1.255, excluding the network address 192.168.1.0 and the broadcast address 192.168.1.255, and the number of IP addresses available in the 192.168.1.0 network is 254. The default Class B network 172.16.0.0 has IP addresses ranging from 172.16.0.0 to 172.16.255.255, excluding network address 172.16.0.0 and broadcast address 172.16.255.255, the number of IP addresses that can be used in the 172.16.0.0 network is 65536-2=65534, where A special reminder is that 172.16.0.255, 172.16.1.255 ...................................................................................................................................................... 172.16.254.255 is not a broadcast address because a Class B network address has 16 host bits, and only 16 bits with all 1s are broadcast addresses. The IP subnetting is described later in this section, so keep in mind that a network address with all 0 host bits is a network address, and a broadcast address with all 1 host bits is a broadcast address.2.5.4 Public IP Addresses and Private IP Addresses** Public IP addresses are unique because they are global and standard, so no two units connected to a publick 39Lining Chapter 2 Network Interconnection and Reference Models*** | 02hosts on the common network have the same IP address. The average broadband access user can apply for a public IP address from an ISP operator for a fee, and with a public IP address, they can provide service to the Internet.With the rapid growth of the Internet, public IP addresses are nearly depleted. To solve this problem, mechanisms such as VLSM (Variable Length SubnetMasks), CIDR (ClasslessInter-DomainRouting), and IPv6 have been proposed. VLSM, CIDR, and IPv6 are discussed in later chapters of this book.Another, more proven approach is to use private addresses. As mentioned earlier, Internet hosts need a globally unique IP address. However, a private network is not connected to the Internet, and it can use any valid IP address. If a private network needs to connect to the Internet, it can use a proxy or a NAT (Network Address Translation) capable device to convert the private IP address to a legitimate public IP address and then access the Internet.In principle, the private network can be configured with any valid IP address, but there is a problem. If the private network is configured with 202.119.248.0, a Class C network, the private network will not be able to access the Web homepage of NUIST because the IP address of the NUIST Web server is 202.119.248.65. To avoid this, RFC1918 sets aside three exclusive IP address blocks (one Class A address block, 16 Class B address blocks, and 256 Class C address blocks, as shown in Table 2-5-2) for private, internal use. IP addresses within these three blocks are not forwarded by routers on the Internet because none of the routers on the Internet are configured to route these IP addresses, and any packets going to these private IP addresses will be dropped by the routers.Table 2.5-2 Private IP AddressesIP Address Classes Address Ranges specified in RFC 1918