1 URLs and HTTP
2 URI Codec: Encoding and Decoding URIs
3 FTP: Client Downloading
4 Send URL: Opening a Web Browser
5 SMTP: Sending E-Mail
6 sendmail: Sending E-Mail
7 Headers: Parsing and Constructing
8 IMAP: Reading Mail
9 POP3: Reading Mail
10 MIME: Decoding Internet Data
11 Base 64: Encoding and Decoding
12 Quoted-Printable: Encoding and Decoding
13 DNS: Domain Name Service Queries
14 NNTP: Newsgroup Protocol
15 TCP: Unit and Signature
16 TCP Redirect: tcp^ via Channels
17 SSL Unit: tcp^ via SSL
18 CGI Scripts
19 Cookie: HTTP Client Storage
Bibliography
Index
On this page:
13.1 Functions
dns-get-address
dns-get-name
dns-get-mail-exchanger
dns-find-nameserver
13.2 DNS Unit
dns@
13.3 DNS Signature
dns^
Version: 4.0.2

 

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.