netconfig(4N) (Networking Services Architecture) netconfig(4N)
NAME
netconfig - network configuration database
SYNOPSIS
#include <netconfig.h>
DESCRIPTION
The network configuration database, /etc/netconfig, is a system file
used to store information about networks connected to the system and
available for use. The netconfig database and the routines that
access it [see getnetconfig(3N)] are part of the UNIX System V
Network Selection component. The Network Selection component also
includes the environment variable NETPATH and a group of routines
that access the netconfig database using NETPATH components as links
to the netconfig entries. NETPATH is described in sh(1); the NETPATH
access routines are discussed in getnetpath(3N).
netconfig contains an entry for each network available on the system.
Entries are separated by newlines. Fields are separated by
whitespace and occur in the order in which they are described below.
Whitespace can be embedded as ``\blank'' or ``\tab''. Backslashes
may be embedded as ``\\''. Each field corresponds to an element in
the struct netconfig structure. struct netconfig and the identifiers
described on this manual page are defined in
/usr/include/netconfig.h.
network ID
A string used to uniquely identify a network. network ID
consists of non-null characters, and has a length of at least
1. No maximum length is specified. This namespace is locally
significant and the local system administrator is the naming
authority. All network IDs on a system must be unique.
semantics
The semantics field is a string identifing the ``semantics'' of
the network, i.e., the set of services it supports, by
identifying the service interface it provides. The semantics
field is mandatory. The following semantics are recognized.
tpiclts Transport Provider Interface, connectionless
tpicots Transport Provider Interface, connection
oriented
tpicotsord
Transport Provider Interface, connection
oriented, supports orderly release.
flag The flag field records certain two-valued (``true'' and
``false'') attributes of networks. flag is a string composed
of a combination of characters, each of which indicates the
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value of the corresponding attribute. If the character is
present, the attribute is ``true.'' If the character is
absent, the attribute is ``false.'' ``-'' indicates that none
of the attributes is present. Only two characters are
currently recognized:
v Visible (``default'') network. Used when the
environment variable NETPATH is unset.
b Network capable of broadcast.
protocol family
The protocol family and protocol name fields are provided for
protocol-specific applications.
The protocol family field contains a string that identifies a
protocol family. The protocol family identifier follows the
same rules as those for network IDs, that is, the string
consists of non-null characters; it has a length of at least 1;
and there is no maximum length specified. A ``-'' in the
protocol family field indicates that no protocol family
identifier applies, that is, the network is experimental. The
following are examples:
loopback Loopback (local to host).
inet Internetwork: UDP, TCP, etc.
implink ARPANET imp addresses
pup PUP protocols: e.g. BSP
chaos MIT CHAOS protocols
ns XEROX NS protocols
nbs NBS protocols
ecma European Computer Manufacturers Association
datakit DATAKIT protocols
ccitt CCITT protocols, X.25, etc.
sna IBM SNA
decnet DECNET
dli Direct data link interface
lat LAT
hylink NSC Hyperchannel
appletalk Apple Talk
nit Network Interface Tap
ieee802 IEEE 802.2; also ISO 8802
osi Umbrella for all families used by OSI (e.g.,
protosw lookup)
x25 CCITT X.25 in particular
osinet AFI = 47, IDI = 4
gosip U.S. Government OSI
protocol name
The protocol name field contains a string that identifies a
protocol. The protocol name identifier follows the same rules
as those for network IDs, that is, the string consists of non-
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netconfig(4N) (Networking Services Architecture) netconfig(4N)
NULL characters; it has a length of at least 1; and there is no
maximum length specified. The following protocol names are
recognized. A ``-'' indicates that none of the names listed
applies.
tcp Transmission Control Protocol
udp User Datagram Protocol
icmp Internet Control Message Protocol
network device
The network device is the full pathname of the device used to
connect to the transport provider. Typically, this device will
be in the /dev directory. The network device must be
specified.
directory lookup libraries
The directory lookup libraries support a ``directory service''
(a name-to-address mapping service) for the network. This
service is implemented by the UNIX System V Name-to-Address
Mapping feature. If a network is not provided with such a
library, the netdir feature will not work. A ``-'' in this
field indicates the absence of any lookup libraries, in which
case name-to-address mapping for the network is non-functional.
The directory lookup library field consists of a comma-
separated list of full pathnames to dynamically linked
libraries. Commas may be embedded as ``\,''; backslashs as
``\\''.
Lines in /etc/netconfig that begin with a sharp sign (#) in column 1
are treated as comments.
The struct netconfig structure includes the following members
corresponding to the fields in in the netconfig database entries:
char * ncnetid Network ID, including NULL
terminator
unsigned long ncsemantics Semantics
unsigned long ncflag Flags
char * ncprotofmly Protocol family
char * ncproto Protocol name
char * ncdevice Full pathname of the network device
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netconfig(4N) (Networking Services Architecture) netconfig(4N)
unsigned long ncnlookups Number of directory lookup libraries
char ** nclookups Full pathnames of the directory
lookup libraries themselves
unsigned long ncunused[9] Reserved for future expansion (not
advertised to user level)
The ncsemantics field takes the following values, corresponding to
the semantics identified above:
NCTPICLTS
NCTPICOTS
NCTPICOTSORD
The ncflag field is a bitfield. The following bits, corresponding
to the attributes identified above, are currently recognized.
NCNOFLAG indicates the absence of any attributes.
NCVISIBLE
NCBROADCAST
SEE ALSO
netdir_getbyname(3N), getnetconfig(3N), getnetpath(3N), netconfig(4N)
Programmer's Guide: Networking Interfaces
System Administrator's Guide
FILES
/etc/netconfig
/usr/include/netconfig.h
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