networks(4) [opensolaris man page]

networks(4)							   File Formats 						       networks(4)

NAME

       networks - network name database

SYNOPSIS

       /etc/inet/networks

       /etc/networks

DESCRIPTION

       The  networks  file  is a local source of information regarding the networks which comprise the Internet. The networks  file can be used in
       conjunction with, or instead of, other networks sources, including the NIS maps	networks.byname and  networks.byaddr and  the  NIS+  table
       networks. Programs use the getnetbyname(3SOCKET) routines to access this information.

       The network file has a single line for each network, with the following information:

	 official-network-name network-number aliases

       Items  are separated by any number of  SPACE or TAB characters. A `#' indicates the beginning of a comment. Characters up to the end of the
       line are not interpreted by routines which search the file. This file is normally created from the official network database maintained	at
       the  Network  Information  Control  Center  (NIC), though local changes may be required to bring it up to date regarding unofficial aliases
       and/or unknown networks.

       Network numbers may be specified in the conventional dot (`.') notation using the inet_network routine from the Internet address  manipula-
       tion library, inet(7P). Network names may contain any printable character other than a field delimiter, NEWLINE, or comment character.

SEE ALSO

       getnetbyaddr(3SOCKET), getnetbyname(3SOCKET), inet(3SOCKET), nsswitch.conf(4), inet(7P)

NOTES

       The official SVR4 name of the networks file is /etc/inet/networks. The symbolic link /etc/networks exists for BSD compatibility.

       The  network number in networks database is the host address shifted to the right by the number of 0 bits in the address mask. For example,
       for the address 24.132.47.86 that has a mask of fffffe00, its network number is 803351. This is obtained when the address is shifted  right
       by  9  bits.  The  address  maps  to 12.66.23. The trailing 0 bits should not be specified.  The network number here is different from that
       described in netmasks(4). For this example, the entry in netmasks would be 24.132.46.0  fffffe00.

SunOS 5.11							    17 Jan 2002 						       networks(4)

Check Out this Related Man Page

GETNETENT(3)						     Linux Programmer's Manual						      GETNETENT(3)

NAME

       getnetent, getnetbyname, getnetbyaddr, setnetent, endnetent - get network entry

SYNOPSIS

       #include <netdb.h>

       struct netent *getnetent(void);

       struct netent *getnetbyname(const char *name);

       struct netent *getnetbyaddr(long net, int type);

       void setnetent(int stayopen);

       void endnetent(void);

DESCRIPTION

       The  getnetent()  function  reads the next line from the file /etc/networks and returns a structure netent containing the broken out fields
       from the line.  The /etc/networks file is opened if necessary.

       The getnetbyname() function returns a netent structure for the line from /etc/networks that matches the network name.

       The getnetbyaddr() function returns a netent structure for the line that matches the network number net of type type.

       The setnetent() function opens and rewinds the /etc/networks file.  If stayopen is true (1), then the file will not be closed between calls
       to getnetbyname() and getnetbyaddr().

       The endservent() function closes /etc/networks.

       The netent structure is defined in <netdb.h> as follows:

	      struct netent {
		      char    *n_name;		/* official network name */
		      char    **n_aliases;	/* alias list */
		      int     n_addrtype;	/* net address type */
		      unsigned long int n_net;	/* network number */
	      }

       The members of the netent structure are:

       n_name The official name of the network.

       n_aliases
	      A zero terminated list of alternative names for the network.

       n_addrtype
	      The type of the network number; always AF_INET.

       n_net  The network number in host byte order.

RETURN VALUE

       The  getnetent(),  getnetbyname() and getnetbyaddr() functions return the netent structure, or a NULL pointer if an error occurs or the end
       of the file is reached.

FILES

       /etc/networks
	      networks database file

CONFORMING TO

       BSD 4.3

SEE ALSO

       getprotoent(3), getservent(3), networks(5)
       RFC 1101

BSD
								    1993-05-15							      GETNETENT(3)

Linux and UNIX Man Pages

networks(4) [opensolaris man page]

Check Out this Related Man Page