ref: ad5a80bfb081dc954be03836cc65090e0f6c7e4f
dir: /man/8/dns/
.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.