Arguments: &key nameserver search domain auto
In order to work, the DNS utility needs to know the IP address of at
least one nameserver willing to respond to recursive queries (that is,
to do the work of the query if it doesn't know the answer). This
function is used to specify the nameserver addresses. It can also
specify other optional information. When DNS is configured, the
variable *dns-configured* is set to true.
| Name | What |
|---|---|
| nameserver | An IP address or a list of IP addresses of the nameservers we should consult |
| search | a list of strings naming the domains we should search in dns-lookup-hostname. |
| domain | the domain of this machine (e.g. "foo.com").
This value is stored in the variable *dns-domain*
for programs to use. |
| auto | If true, determine as much of this information as possible automatically, overriding the values set by the other arguments. |
We would like to be able to compute this information automatically in every situation. Currently we can handle Unix machines that specify this information in a file called /etc/resolv.conf, and we try to handle all versions of Windows (but see the note under the heading Automatic DNS configuation on Windows below).
When dns-query is
called, it checks to see if configure-dns has been
called since lisp started, and if not it calls
configure-dns with :auto t. If
this doesn't work it means that you need to call
configure-dns with the appropriate information before
you call dns-query on this
machine.
On Windows the information we need to automatically configure this
module is found in the Windows registry. Unfortunately the information
we need is in a different place in each on the six Windows
configurations we tested (Win98, Win NT 4, Win2000, each with a fixed
IP address or using DCHP to configure the IP address). Therefore it's
likely that information will move around again in future version of
Windows. Furthermore sometimes we encounter stale information in the
registry (for example, a laptop computer that used to be on a network
but isn't at the moment may hold the last known nameserver information
in the registry even though those nameservers are
unreachable). Therefore, if you wish to make use of the
Allegro CL DNS facility,
you should be prepared to manually configure-dns on machines (by
calling this function with autonil and filling in the necessary information) when
auto configuration fails.
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.
The documentation is described in introduction.htm and the index is in index.htm.
Copyright (c) 1998-2000, Franz Inc. Berkeley, CA., USA. All rights reserved.
Created 2000.10.5.