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14.1 Functions
dns-get-address
dns-get-name
dns-get-mail-exchanger
dns-find-nameserver
14.2 DNS Unit
dns@
14.3 DNS Signature
dns^

14 DNS: Domain Name Service Queries

The net/dns library provides utilities for looking up hostnames.
Thanks to Eduardo Cavazos and Jason Crowe for repairs and improvements.

14.1 Functions

procedure

(dns-get-address nameserver    
  address    
  [#:ipv6? ipv6?])  string?
  nameserver : string?
  address : string?
  ipv6? : any/c = #f
Consults the specified nameserver (normally a numerical address like "128.42.1.30") to obtain a numerical address for the given Internet address.

The query record sent to the DNS server includes the "recursive" bit, but dns-get-address also implements a recursive search itself in case the server does not provide this optional feature.

If ipv6? is a true value, then the numerical address that is returned will be an IPv6 address. If no AAAA record exists, an error will be raised.

procedure

(dns-get-name nameserver address)  string?

  nameserver : string?
  address : string?
Consults the specified nameserver (normally a numerical address like "128.42.1.30") to obtain a name for the given numerical address.

procedure

(dns-get-mail-exchanger nameserver address)  string?

  nameserver : string?
  address : string?
Consults the specified nameserver to obtain the address for a mail exchanger the given mail host address. For example, the mail exchanger for "ollie.cs.rice.edu" might be "cs.rice.edu".

Attempts to find the address of a nameserver on the present system. On Unix and Mac OS X, this procedure parses "/etc/resolv.conf" to extract the first nameserver address. On Windows, it runs nslookup.exe.

14.2 DNS Unit

dns@ and dns^ are deprecated. They exist for backward-compatibility and will likely be removed in the future. New code should use the net/dns module.

 (require net/dns-unit)

value

dns@ : unit?

Imports nothing, exports dns^.

14.3 DNS Signature

 (require net/dns-sig)

signature

dns^ : signature

Includes everything exported by the net/dns module.