Thus, the services that ultimately receive them respond according to the specified destination. Looped-back packets are distinguished from any other packets traversing the TCP/IP stack only by the special IP address they were addressed to. This permits software testing and local services, even in the absence of any hardware network interfaces. Such packets are never passed to any network interface controller (NIC) or hardware device driver and must not appear outside of a computing system, or be routed by any router. The processing of any packet sent to a loopback address, is implemented in the link layer of the TCP/IP stack. Its purpose and definition was unchanged in 1998,, 2003,, and up to the current definition, in 2006. įrom the outset, in 1995, the single IPv6 loopback address ::1 was defined. Its purpose as a Special Use IPv4 Address block was confirmed in 1994,, 2002, 2010,, and last in 2013. This block was officialy assigned for loopback purposes in 1986. In 1981, the block 127.0.0.0 / 8 got a 'reserved' status, as not to assign it as a general purpose class A IP network. Domain name registrars are precluded from delegating domain names in the top-level. localhost is reserved as a top-level domain name, originally set aside to avoid confusion with the hostname localhost. The mapping of localhost to addresses other than the designated loopback address range in the hosts file or in DNS is not guaranteed to have the desired effect, as applications may map the name internally. In addition to the mapping of localhost to the loopback addresses ( 127.0.0.1 and ::1), localhost may also be mapped to other IPv4 (loopback) addresses and it is also possible to assign other, or additional, names to any loopback address. When authoritative name servers receive queries for 'localhost' in spite of the provisions mentioned above, they should resolve them appropriately.To avoid burdening the Domain Name System root servers with traffic, caching name servers should never request name server records for localhost, or forward resolution to authoritative name servers.Queries for localhost should not be sent to caching name servers. When a name resolver receives an address (A or AAAA) query for localhost, it should return the appropriate loopback addresses, and negative responses for any other requested record types.Applications may resolve the name to a loopback address themselves, or pass it to the local name resolver mechanisms.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |