13 DNS: Domain Name Service Queries

(require net/dns)

The net/dns library provides utilities for looking up hostnames.

Thanks to Eduardo Cavazos and Jason Crowe for repairs and improvements.

13.1 Functions

(dns-get-address nameserver address) → string?

nameserver : string?

address : string?

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.

(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.

(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".

(dns-find-nameserver) → (or/c string? false/c)

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

13.2 DNS Unit

(require net/dns-unit)

dns@ : unit?

Imports nothing, exports dns^.

13.3 DNS Signature

(require net/dns-sig)

dns^ : signature

Includes everything exported by the net/dns module.