NAME

ndb − Network database

DESCRIPTION

The network database consists of files describing machines known to the local installation and machines known publicly.  The files comprise multi-line tuples made up of attribute/value pairs of the form attr=value or sometimes just attr. Each line starting without white space starts a new tuple. Lines starting with ­# are comments. 

The file ­/lib/ndb/local is the root of the database.  Other files are included in the database if a tuple with an attribute-value pair of attribute ­database and no value exists in /lib/ndb/local .  Within the ­database tuple, each tuple with attribute ­file identifies a file to be included in the database.  The files are searched in the order they appear.  For example:

database=
file=/lib/ndb/common
file=/lib/ndb/local
file=/lib/ndb/global

declares the database to be composed of the three files /lib/ndb/common, /lib/ndb/local, and /lib/ndb/global.  By default, ­/lib/ndb/local is searched before the others.  However, ­/lib/ndb/local may be included in the ­database to redefine its ordering. 

Within tuples, pairs on the same line bind tighter than pairs on different lines. 

The program ­ndb/cs (see ndb(8)) and the library routine ­ipinfo (see ndb(2)) perform searches for information relative to a particular host. Ndb/cs resolves meta-addresses of the form $attribute by returning the ­value from the attribute=value most closely related to the resolving host.  The attribute-value pair comes from the tuple for the system, its subnet, or its network with the system tuple having precedence, subnet next, and network last. 

A number of attributes are meaningful to programs and thus reserved.  They are:

­sys system name

­dom Internet domain name

­ip Internet address

­ether Ethernet address

­dk Datakit address

­bootf file to download for initial bootstrap

­ipnet Internet network name

­ipmask Internet network mask

­ipgw Internet gateway

­auth authentication server to be used

­fs file server to be used

­tcp a TCP service name

­udp a UDP service name

­il an IL service name

­port a TCP, UDP, or IL port number

­restricted
a TCP service that can be called only by ports numbered less that 1024

­proto a protocol supported by a host.  The pair ­proto=il is needed by ­cs (see ndb(8)) in tuples for hosts that support the IL protocol.

­9P parameters for the 9P file protocol, in particular whether the server authenticates (9P=auth). 

The file ­/lib/ndb/auth is used during authentication to decide who has the power to ‘speak for’ other users; see auth(6).

EXAMPLES

A tuple for the CPU server, spindle. 

sys = spindle
dom=spindle.research.att.com
bootf=/mips/9powerboot
ip=135.104.117.32 ether=080069020677
dk=nj/astro/spindle
proto=il

Entries for the network ­mh-astro-net and its subnets. 

ipnet=mh-astro-net ip=135.104.0.0 ipmask=255.255.255.0
fs=bootes.research.att.com
ipgw=r70.research.att.com
auth=p9auth.research.att.com
ipnet=unix-room ip=135.104.117.0
ipgw=135.104.117.1
ipnet=third-floor ip=135.104.51.0
ipgw=135.104.51.1

Mappings between TCP service names and port numbers. 

tcp=sysmonport=401
tcp=rexecport=512restricted
tcp=9fsport=564

FILES

­/lib/ndb/local
first database file searched

­/lib/ndb/global
second database file searched

SEE ALSO

dial(2), ndb(2), ndb(8), bootp(8), ipconfig(8), con(1)

Plan 9  —  April 04, 1995