netconfig(4) FILE FORMATS netconfig(4)
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 con-
nected 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 dis-
cussed 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 ser-
vices it supports, by identifying the service inter-
face it provides. The semantics field is mandatory.
The following semantics are recognized.
tpiclts Transport Provider Interface, connec-
tionless
tpicots Transport Provider Interface, connec-
tion oriented
tpicotsord
Transport Provider Interface, connec-
tion oriented, supports orderly
release.
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netconfig(4) FILE FORMATS netconfig(4)
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 value of the corresponding
attribute. If the character is present, the attribute
is ``true.'' If the character is absent, the attri-
bute is ``false.'' ``-'' indicates that none of the
attributes is present. Only one character is
currently recognized:
v Visible (``default'') network. Used
when the environment variable NETPATH
is unset.
protocol family
The protocol family and protocol name fields are pro-
vided for protocol-specific applications.
The protocol family field contains a string that iden-
tifies a protocol family. The protocol family iden-
tifier follows the same rules as those for network
IDs, that is, the string consists of non-null charac-
ters; 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 iden-
tifier 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 Asso-
ciation
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
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netconfig(4) FILE FORMATS netconfig(4)
protocol name
The protocol name field contains a string that identi-
fies a protocol. The protocol name 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. The following protocol names are recog-
nized. 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 net-
work 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 Sys-
tem 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 indi-
cates the absence of any lookup libraries, in which
case name-to-address mapping for the network is non-
functional. The directory lookup library field con-
sists 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 netcon-
fig structure includes the following members
corresponding to the fields in in the netconfig data-
base entries:
char * ncnetid Network ID, including NULL
terminator
unsigned long ncsemantics Semantics
unsigned long ncflag Flags
char * ncprotofmly Protocol family
char * ncproto Protocol name
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netconfig(4) FILE FORMATS netconfig(4)
char * ncdevice Full pathname of the net-
work device
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 expan-
sion (not advertised to
user level) The
ncsemantics field takes
the following values,
corresponding to the seman-
tics identified above:
NCTPICLTS
NCTPICOTS
NCTPICOTSORD
The ncflag field is a bitfield. The following bit,
corresponding to the attribute identified above, is
currently recognized. NCNOFLAG indicates the absence of any
attributes.
NCVISIBLE
SEE ALSO
netdir_getbyname(3N), getnetconfig(3N), getnetpath(3N),
netconfig(4)
Network Programmer's Guide
System Administrator's Guide
FILES
/etc/netconfig
/usr/include/netconfig.h
structure? Nancy Yeager says applications need to know
about it. Can you supply it and where does it go? <=]
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