TH NDB 6
SH NAME
ndb \- Network database
SH DESCRIPTION
PP
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
IB attr = value
or sometimes just
IR attr .
Each line starting without white space starts a new tuple.
Lines starting with
B #
are comments.
PP
The file
B /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
B database
and no value exists in
BR /lib/ndb/local
Within the
B database
tuple,
each tuple with attribute
B file
identifies a file to be included in the database.  The files are searched
in the order they appear.
For example:
IP
EX
database=
       file=/lib/ndb/common
       file=/lib/ndb/local
       file=/lib/ndb/global
EE
PP
declares the database to be composed of the three files
BR /lib/ndb/common ,
BR /lib/ndb/local ,
and
BR /lib/ndb/global .
By default,
B /lib/ndb/local
is searched before the others.
However,
B /lib/ndb/local
may be included in the
B database
to redefine its ordering.
PP
Within tuples, pairs on the same line bind tighter than
pairs on different lines.
PP
Programs search the database directly using the routines in
IR ndb (2)
or indirectly using
B ndb/cs
and
B ndb/dns
(see
IR ndb (8)).
Both
B ndb/cs
and the routine
I ndbipinfo
impose structure on the otherwise flat database by using
knowledge specific to the network.
The internet is made up of networks which can be subnetted
multiple times.  A network must have an
B ipnet
attribute and is uniquely identified by the values of it's
B ip
and
B ipmask
attributes.  If the
B ipmask
is missing, the relevant Class A, B or C one is used.
The network is subnetted if one or more
BR ipsubmask 's
are specified.
A search for an attribute associated with a network or host starts
at the top-level Class A, B, or C network and works it's way down to the
specific entry.  The attribute/value chosen is the one lowest down in the
search, i.e, closest to the host.
For example, consider at the following entries:
IP
EX
ipnet=murray-hill ip=135.104.0.0 ipmask=255.255.0.0
       ipsubmask=255.255.255.0
       dns=135.104.10.1
       ntp=ntp.cs.bell-labs.com
ipnet=plan9 ip=135.104.9.0 ipmask=255.255.255.0
       ntp=oncore.cs.bell-labs.com
       smtp=smtp1.cs.bell-labs.com
ip=135.104.9.6 sys=anna dom=anna.cs.bell-labs.com
       smtp=smtp2.cs.bell-labs.com
EE
LP
Here
B anna
is on the subnet
B plan9
which is in turn on the class B net
BR murray-hill .
If one were to search for
BR anna 's
B NTP
and
B SMTP
servers, one would get
B oncore.cs.bell-labs.com
and
B smtp2.cs.bell-labs.com
respectively.
PP
I Ndb/cs
can be made to perform such network aware
searches by using metanames in the dialstring.
A metaname is a
I $
followed by an attribute name.
I Ndb/cs
looks up the attribute relative to the system it is running
on.  Thus, with the above example, if a program called
IP
EX
       dial("tcp!$smtp!smtp", 0, 0, 0);
EE
LP
the dial would connect to the SMTP port of
BR smtp2.cs.bell-labs.com .
PP
A number of attributes are meaningful to programs and thus
reserved.
They are:
TF restricted
TP
B sys
system name
TP
B dom
Internet domain name
TP
B ip
Internet address
TP
B ether
Ethernet address
TP
B bootf
file to download for initial bootstrap
TP
B ipnet
Internet network name
TP
B ipmask
Internet network mask
TP
B ipsubmask
Internet network mask of this network's subnets
TP
B ipgw
Internet gateway
TP
B auth
authentication server to be used
TP
B fs
file server to be used
TP
B tcp
a TCP service name
TP
B udp
a UDP service name
TP
B il
an IL service name
TP
B port
a TCP, UDP, or IL port number
TP
B restricted
a TCP service that can be called only by ports numbered
less that 1024
TP
B proto
a protocol supported by a host.
The pair
B proto=il
is needed by
I cs
(see
IR ndb (8))
in tuples for hosts that support the IL protocol
TP
B dnsdomain
a domain name that
I ndb/dns
adds onto any unrooted names when doing a search
There may be multiple
B dnsdomain
pairs.
TP
B dns
a DNS server to use (for DNS and DHCP)
TP
B ntp
an NTP server to use (for DHCP)
TP
B smtp
an SMTP server to use (for DHCP)
TP
B time
a time server to use (for DHCP)
TP
B wins
a Windows name server (for DHCP)
TP
B mx
mail exchanger (for DNS and DHCP)
TP
B soa
start of area (for DNS)
sp
PD
PP
The file
B /lib/ndb/auth
is used during authentication to decide who has the power to `speak for' other
users; see
IR auth (6).
SH EXAMPLES
LP
A tuple for the CPU server, spindle.
LP
EX
sys = spindle
       dom=spindle.research.bell-labs.com
       bootf=/mips/9powerboot
       ip=135.104.117.32 ether=080069020677
       proto=il
EE
LP
Entries for the network
B mh-astro-net
and its subnets.
LP
EX
ipnet=mh-astro-net ip=135.104.0.0 ipmask=255.255.255.0
       fs=bootes.research.bell-labs.com
       ipgw=r70.research.bell-labs.com
       auth=p9auth.research.bell-labs.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
EE
LP
Mappings between TCP service names and port numbers.
LP
EX
ta \w'\fLtcp=sysmonxxxxx'u \w'\fLtcp=sysmonxxxxxport=512xxx'u
tcp=sysmon      port=401
tcp=rexec       port=512        restricted
tcp=9fs port=564
EE
SH FILES
TP
B /lib/ndb/local
first database file searched
SH "SEE ALSO"
IR dial (2),
IR ndb (2),
IR ndb (8),
IR dhcpd (8),
IR ipconfig (8),
IR con (1)

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