What are the main components of the internet

What is the Internet Protocol?

In order for the datagrams to be able to carry out the elementary specification of the source and destination address in their header, they must first be assigned to the network participants. Traditionally, it is important to distinguish between internal and external or public IP addresses. For the former, which are used for communication in local networks, three address ranges are reserved:

  • to
  • through
  • to

The prefix “fc00 :: / 7” is intended for IPv6 networks. Addresses of these areas are not routed on the Internet and can therefore be freely selected and used in private networks or company networks. The assignment of an address succeeds either bymanual input or finds automatically instead of as soon as a device connects to the network - provided that automatic address assignment is activated and a DHCP server is in use. With the help of a subnet mask, such a local network can also be optionally segmented into further areas.

External IP addresses are assigned to routers automatically assigned by the respective internet providerwhen they connect to the Internet. All devices that are on the Internet via a shared router use the same external IP accordingly. The providers usually assign a new Internet address every 24 hours from an address range that was in turn assigned to them by the IANA. This also applies to the virtually inexhaustible arsenal of IPv6 addresses, which are only partially approved for normal use. Furthermore, it is not only divided into private and public addresses, but is characterized by much more versatile classification options in so-called areas of validity (Address scopes) out:

  • Host scope: The address 0: 0: 0: 0: 0: 0: 0: 1, known as loopback, can be used by a host to send IPv6 datagrams to itself.
  • Link-local scope: For IPv6 connectivity it is of fundamental importance that each host has its own address, even if this is only valid in a local network. This link-local address is identified by the prefix “fe80 :: / 10” and is required, for example, for communication with the standard gateway (router) in order to be able to generate a public IP address.
  • Unique local scope: This is the address area "fc00 :: / 7", which has already been discussed and which is reserved exclusively for the configuration of local networks.
  • Site-local scope: The Site-Local-Scope is an outdated address range with the prefix “fec0 :: / 10”, which was also defined for local networks. However, when different networks were merged or when VPN connections were established between networks that were numbered with site-local addresses, complications arose, which is why the standard was classified as obsolete.
  • Global scope: Every host that wants to establish a connection to the Internet needs at least its own public address. He obtains this via auto-configuration, using either the SLAAC (stateless address configuration) or DHCPv6 (state-oriented address configuration).
  • Multicast scope: Network nodes, routers, servers and other network services can be combined in multicast groups with IPv6. Each of these groups has its own address, which means that all the hosts involved can be reached with a single packet. The prefix "ff00 :: / 8" indicates that a multicast address follows.