| Allegro CL version 9.0 Unrevised from 8.2 to 9.0. 8.2 version | ||||||||||
Arguments: name &key type nameserver repeat timeout queue decode search ignore-cache
The arguments are:
| Name | Default | What |
|---|---|---|
| name | Depending on the value of the type argument, this is either a string or an integer IP address. | |
| type | :a |
The type of dns query to make.:a means determine
the ip address(es) for the given name. (name
should be a string.):ptr means determine the
hostname for a given IP address.
(name
should be an integer IP address, a string containing a
dotted IP address, or an IPv6 address.
:mx means determine if there is
another machine that email for name
should be directed. (name
should be a string.):txt means get all TXT records associated with
name. The answer is a list containing
one or more strings (TXT records can be composed of
multiple strings), or nil if there are no
TXT records. If there is more than one TXT record, then the third
return value will contain a list of the remaining answers.
:aaaa means look up IPv6 adresses.
:any means return
all information about the first argument. decode
should be specified nil (its default is
t) when
type is :any. |
| nameserver | nil |
If specified this can be an IP address or a list of IP addresses. This overrides the configured list of nameservers for just this query. |
| repeat | 5 | How many times to try to get an answer to this query before giving up. |
| timeout | 5 | How long to wait until we assume that a try has failed and we then try again or give up. The value should be an integer indicating a number of seconds. |
| queue | t |
If true then handle this request using the
background process that is
backed up by a cache of recent answers.
If this is nil then a
request will always be sent to the nameserver |
| decode | t |
The nameserver returns a structure of many fields.
If true then dns-query
will examine the returned structures and will return only the
information requested by the
query.
If this is nil then the result of
dns-query will
be the actual information returned by the nameserver.
This response is a dns-response object. See that
page for information on this raw object. Please specify
nil when you specify :any
as the value of type. |
| search | nil |
When specified true,
*dns-domain* and
*domain-search-list* will be used to
fully qualify the name argument before doing the query. See below for
details on how the search is conducted.
|
| ignore-cache |
nil
|
Allegro CL DNS caches positive and negative responses for at least the time-to-live specified in the respones. If dns-query is called again with the same request before the time-to-live expires, the cached information will be returned immediately. If ignore-cache is true, then the cached value will be ignored and a DNS lookup will occur. |
If either nameserver is non-nil or decode is nil, then queue will be set to
nil regardless of the value of
queue supplied. This ensures that a fresh query
is sent to the nameserver.
Where an IP address is a valid argument, it can be specified as either an integer or as a string such as "192.132.95.1" or "127.1". Ipv6 address structures and IPv6 colon hex strings are allowed too.
When the search keyword argument is specified
true, and so *dns-domain* and *domain-search-list* are used to fully
qualify the name argument before doing the query, the search steps are
as follows:
*dns-domain* followed by *domain-search-list*. If
the given name ends in a period (e.g. www.cnn.com.)
then that is an absolute name. Only that name is checked and the
search list is not used.
www.cnn.com) then that name is checked
first.
:no-such-domain
then the next item in the search list is used.
Thus the first response from the search (with a positive or negative valid time, which is the second returned value) is returned as the first returned value, but illegal domains in the search list are ignored.
There are four return values from dns-query.
There are examples of using dns-query in the subsections of The DNS API in dns.htm.
See dns.htm for information on the domain naming system utility in Allegro CL and see socket.htm for general information on sockets in Allegro CL.
Copyright (c) 1998-2019, Franz Inc. Oakland, CA., USA. All rights reserved.
This page was not revised from the 8.2 page.
Created 2012.5.30.
| Allegro CL version 9.0 Unrevised from 8.2 to 9.0. 8.2 version | ||||||||||