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dns, dnsquery - domain name service


ndb/dns [ -f dnsfile ] [ -h ] [ -r ] [ -x net ]

ndb/dnsquery [ -x net ] [ -s server ] [ address ... ]


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/dns) for a translation of each address and prints the results, one per line. If no address is given, dnsquery prompts for something 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 data currently known locally for name
name for which name is an alias
host and operating system type
for an IP address when name is a domain name
mail exchanger
for a list of name servers
for the domain name when name is an Internet address

Dnsquery queries the server for that name/attribute combination and prints the results, one per line. If an attribute is not given, dnsquery uses ip if name looks like a domain name, and ptr if it looks like an Internet address.


service directory
domain name service
network database
DNS bootstrap data




dns(6), cs(8)


Dns does not yet offer an external DNS server, mainly for lack of a suitable database for local zone data.

DNS(8 ) Rev:  Tue Mar 31 02:42:38 GMT 2015