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