netconfig - network configuration database
The network configuration database, /etc/netconfig, is a system file used to store information about networks that are connected to the
system. The netconfig database and the routines that access it (see getnetconfig(3NSL)) are part of the Network Selection component. The
Network Selection component also includes getnetpath(3NSL) routines to provide application-specific network search paths. These routines
access the netconfig database based on the environment variable NETPATH. See environ(5).
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 ``lank'' or `` ab''. Backslashes may be embedded
as ``\''. Lines in /etc/netconfig that begin with a # (hash) in column 1 are treated as comments.
Each of the valid lines in the netconfig database correspond to an available transport. Each entry is of the form:
network ID semantics flag protocol-family
protocol-name network-device translation-libraries
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 identifying the ``semantics'' of the network, that is, the set of services it sup-
ports, by identifying the service interface it provides. The semantics field is mandatory. The following semantics
tpi_clts Transport Provider Interface, connectionless
tpi_cots Transport Provider Interface, connection oriented
tpi_cots_ord 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 com-
posed 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 attribute is ``false.'' ``-''
indicates that none of the attributes are 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 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; 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 (the network is experimental). The following are examples:
loopback Loopback (local to host).
inet Internetwork: UDP, TCP, and the like.
inet6 Internetwork over IPv6: UDP, TCP, and the like.
implink ARPANET imp addresses
pup PUP protocols: for example, 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, and the like.
sna IBM SNA
dli Direct data link interface
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 (for example, 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-NULL characters, it has a length of at least 1,
and there is no maximum length specified. A ``-'' indicates that none of the names listed apply. The following pro-
tocol names are recognized.
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.
translation libraries The name-to-address translation libraries support a ``directory service'' (a name-to-address mapping service) for
the network. A ``-'' in this field indicates the absence of any translation libraries. This has a special meaning
for networks of the protocol family inet : its name-to-address mapping is provided by the name service switch based
on the entries for hosts and services in nsswitch.conf(4). For networks of other families, a ``-'' indicates non-
functional name-to-address mapping. Otherwise, this field consists of a comma-separated list of pathnames to dynam-
ically linked libraries. The pathname of the library can be either absolute or relative. See dlopen(3C).
Each field corresponds to an element in the struct netconfig structure. struct netconfig and the identifiers described on this manual page
are defined in <netconfig.h>. This structure includes the following members:
char *nc_netid Network ID, including NULL terminator.
unsigned long nc_semantics Semantics.
unsigned long nc_flag Flags.
char *nc_protofmly Protocol family.
char *nc_proto Protocol name.
char *nc_device Full pathname of the network device.
unsigned long nc_nlookups Number of directory lookup libraries.
char **nc_lookups Names of the name-to-address translation libraries.
unsigned long nc_unused Reserved for future expansion.
The nc_semantics field takes the following values, corresponding to the semantics identified above:
NC_TPI_COTS_ORD The nc_flag field is a bitfield. The following bit, corresponding to the attribute identified above, is currently
recognized. NC_NOFLAG indicates the absence of any attributes.
Example 1: A Sample netconfig File
Below is a sample netconfig file:
# The "Network Configuration" File.
# Each entry is of the form:
# <networkid> <semantics> <flags> <protofamily> <protoname> <device>
# The "-" in <nametoaddrlibs> for inet family transports indicates
# redirection to the name service switch policies for "hosts" and
# "services". The "-" may be replaced by nametoaddr libraries that
# comply with the SVr4 specs, in which case the name service switch
# will not be used for netdir_getbyname, netdir_getbyaddr,
# gethostbyname, gethostbyaddr, getservbyname, and getservbyport.
# There are no nametoaddr_libs for the inet family in Solaris anymore.
udp6 tpi_clts v inet6 udp /dev/udp6 -
tcp6 tpi_cots_ord v inet6 tcp /dev/tcp6 -
udp tpi_clts v inet udp /dev/udp -
tcp tpi_cots_ord v inet tcp /dev/tcp -
rawip tpi_raw - inet - /dev/rawip -
ticlts tpi_clts v loopback - /dev/ticlts straddr.so
ticotsord tpi_cots_ord v loopback - /dev/ticotsord straddr.so
ticots tpi_cots v loopback - /dev/ticots straddr.so
dlopen(3C), getnetconfig(3NSL), getnetpath(3NSL), nsswitch.conf(4)
18 Nov 2003 netconfig(4)