What is AF INET and why do I need it

Question

I m getting started on socket programming  and I keep seeing this AF INET   Yet  I ve never seen anything else used in its place  My lecturers are not that helpful and just say  You just need it    So my questions    What is the purpose of AF INET  Is anything else ever used instead of it    If not  why is it there  For possible changes in the future  If so  what and why

User · Answer

Socket are characterized by their domain, type and transport protocol. Common domains are:

AF_UNIX: address format is UNIX pathname
AF_INET: address format is host and port number

(there are actually many other options which can be used here for specialized purposes).usually we use AF_INET for socket programming

Reference: http://www.cs.uic.edu/~troy/fall99/eecs471/sockets.html

User · Answer

AF INET is an address family that is used to designate the type of addresses that your socket can communicate with  in this case  Internet Protocol v4 addresses   When you create a socket  you have to specify its address family  and then you can only use addresses of that type with the socket  The Linux kernel  for example  supports 29 other address families such as UNIX  AF UNIX  sockets and IPX  AF IPX   and also communications with IRDA and Bluetooth  AF IRDA and AF BLUETOOTH  but it is doubtful you ll use these at such a low level    For the most part  sticking with AF INET for socket programming over a network is the safest option   There is also AF INET6 for Internet Protocol v6 addresses   Hope this helps

User · Answer

it defines the protocols address family this determines the type of socket created  pocket pc support AF INET   the content in the following page is quite decent http   etutorials org Programming Pocket pc network programming Chapter 1  Winsock Streaming TCP Sockets

User · Answer

The primary purpose of AF INET was to allow for other possible network protocols or address families  AF is for address family  PF INET is for the  IPv4  internet protocol family    For example  there probably are a few Netware SPX IPX networks around still  there were other network systems like DECNet  StarLAN and SNA  not to mention the ill-begotten ISO OSI  Open Systems Interconnection   and these did not necessarily use the now ubiquitous IP address to identify the peer host in network connections   The ubiquitous alternative to AF INET  which  in retrospect  should have been named AF INET4  is AF INET6  for the IPv6 address family   IPv4 uses 32-bit addresses  IPv6 uses 128-bit addresses   You may see some other values - but they are unusual   It is there to allow for alternatives and future directions   The sockets interface is actually very general indeed - which is one of the reasons it has thrived where other networking interfaces have withered   Life has  mostly  gotten simpler - be grateful

User · Answer

You need arguments like AF UNIX or AF INET to specify which type of socket addressing you would be using to implement IPC socket communication  AF stands for Address Family   As in BSD standard Socket  adopted in Python socket module  addresses are represented as follows    A single string is used for the AF UNIX AF LOCAL address family  This option is used for IPC on local machines where no IP address is required  A pair  host  port  is used for the AF INET address family  where host is a string representing either a hostname in Internet domain notation like  daring cwi nl  or an IPv4 address like  100 50 200 5   and port is an integer  Used to communicate between processes over the Internet    AF UNIX   AF INET6   AF NETLINK   AF TIPC   AF CAN   AF BLUETOOTH   AF PACKET   AF RDS are other option which could be used instead of AF INET   This thread about the differences between AF INET and PF INET might also be useful

[sockets] What is AF_INET, and why do I need it?

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