Search results
Results from the WOW.Com Content Network
Used for local communications within a private network [3] 100.64.0.0/10 100.64.0.0–100.127.255.255 4 194 304: Private network Shared address space [4] for communications between a service provider and its subscribers when using a carrier-grade NAT: 127.0.0.0/8 127.0.0.0–127.255.255.255 16 777 216: Host Used for loopback addresses to the ...
The first header field in an IP packet is the Version field. For IPv4, this is always equal to 4. Internet Header Length (IHL): 4 bits The IPv4 header is variable in size due to the optional 14th field (Options). The IHL field contains the size of the IPv4 header; it has 4 bits that specify the number of 32-bit words in the header.
The original list of IPv4 address blocks was published in September 1981. [3] In previous versions of the document, [19] [20] network numbers were 8-bit numbers rather than the 32-bit numbers used in IPv4. At that time, three networks were added that were not listed earlier: 42.rrr.rrr.rrr, 43.rrr.rrr.rrr, and 44.rrr.rrr.rrr.
The Internet Engineering Task Force (IETF) has reserved the IPv4 address block 169.254.0.0 / 16 (169.254.0.0 – 169.254.255.255) for link-local addressing. [1] The entire range may be used for this purpose, except for the first 256 and last 256 addresses (169.254.0.0 / 24 and 169.254.255.0 / 24), which are reserved for future use and must not be selected by a host using this dynamic ...
A special case of private link-local addresses is the loopback interface. These addresses are private and link-local by definition since packets never leave the host device. IPv4 reserves the entire class A address block 127.0.0.0 / 8 for use as private loopback addresses. IPv6 reserves the single address ::1.
That means any packet sent to any of those addresses is looped back. The address 127.0.0.1 is the standard address for IPv4 loopback traffic; the rest are not supported by all operating systems. However, they can be used to set up multiple server applications on the host, all listening on the same port number.
The first working version that was widely deployed was assigned version number 4. [10] A separate protocol based on reliable connections was developed and assigned version 5. IP version 7 was chosen in 1988 by R. Ullmann as the next IP version because he incorrectly assumed that version 6 was in use for ST-II.
The name localhost is a commonly defined hostname for the loopback interface in most TCP/IP systems, resolving to the IP addresses 127.0.0.1 in IPv4 and ::1 for IPv6.As a top-level domain, the name has traditionally been defined statically in host DNS implementations with address records (A and AAAA) pointing to the same loopback addresses.