code: 9ferno

ref: e81c54ba2ecc673a4d5f8aed0e9b52841fe07b0d
dir: /man/8/dns/

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.TH DNS 8
.SH NAME
dns, dnsquery \- domain name service
.SH SYNOPSIS
.B ndb/dns
[
.BI -f " dnsfile"
] [
.B -h
] [
.B -r
] [
.BI -x " net"
]
.PP
.B ndb/dnsquery
[
.BI -x " net"
] [
.BI -s " server"
] [
.I "address ..."
]
.SH DESCRIPTION
.I Dns
is an Internet Domain Name Service (DNS) resolver.
By default it serves a file
.BR /net/dns ,
that clients such as
.IR cs (8)
write and read to retrieve network data associated with domain names and Internet addresses.
The
.B -f
option specifies the network database that contains the local DNS data (default:
.BR /lib/ndb/local ).
The
.B -x
option specifies an alternative mount point for the network (default:
.BR /net ).
When Inferno is running hosted,
.I dns
normally uses the host's own DNS resolver first (via
.IR srv (2)),
before searching the DNS itself; that way domain names can be
used in Inferno with minimal configuration.
The
.B -h
option stops
.I dns
from using the host data.
In the absence of local data, by default
.I dns
consults the external DNS directly using some bootstrap data, but if
.B -r
is specified and local resolvers are given in the configuration file,
.IR dns (6),
.I dns
will query them first for all addresses, before resorting to external DNS servers.
.PP
.I Dnsquery
queries the given
.I server
(default:
.BR /net/dns )
for a translation of each
.I address
and prints the results, one per line.
If no
.I address
is given,
.I dnsquery
prompts for something to find in the DNS, one per line on the standard input,
of the form:
.IP
.EX
.IR "name" " [" attribute "]"
.EE
.PP
where
.I name
is the label of something in the DNS, and
.I attribute
is one of its attributes from the list below:
.TF hinfox
.TP
.B all
all data currently known locally for
.I name
.TP
cname
name for which
.I name
is an alias
.TP
hinfo
host and operating system type
.TP
.B ip
for an IP address when
.I name
is a domain name
.TP
.B mx
mail exchanger
.TP
.B ns
for a list of name servers
.TP
.B ptr
for the domain name when
.I name
is an Internet address
.TP
.B soa
statement-of-authority
.PD
.PP
.I Dnsquery
queries the
.I server
for that name/attribute combination and prints the results, one per line.
If an
.I attribute
is not given,
.I dnsquery
uses
.B ip
if
.I name
looks like a domain name,
and
.B ptr
if it looks like an Internet address.
.SH FILES
.TF /lib/ndb/local
.TP
.B #sdns*
service directory
.TP
.B /net/dns
domain name service
.TP
.B /lib/ndb/local
network database
.TP
.B /lib/ndb/dns
DNS bootstrap data
.SH SOURCE
.B /appl/cmd/ndb/dns.b
.br
.B /appl/cmd/ndb/dnsquery.b
.SH "SEE ALSO"
.IR dns (6),
.IR cs (8)
.SH BUGS
.I Dns
does not yet offer an external DNS server, mainly
for lack of a suitable database for local zone data.