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| Allegro CL version 10.1 Unrevised from 10.0 to 10.1. 10.0 version

## *dns-mode*

This variable can have the value `:clib` or `:acldns` or a list of one or both of those symbols. The initial value is the list `(:acldns :clib)`.

The value of this variable controls whether the C library functions or Allegro CL DNS functionality are used for calls to lookup-hostname and ipaddr-to-hostname. Using Allegro CL DNS functionality means calls are made to dns-lookup-hostname and dns-ipaddr-to-hostname.

If the value of this variable is either `:acldns` or the list `(:acldns)` then lookup-hostname and ipaddr-to-hostname use Allegro CL DNS functionality.

If the value of this variable is either `:clib` or the list `(:clib)` then lookup-hostname and ipaddr-to-hostname use the C library functions to do the dns lookup.

If the value of this variable is a list containing both `:clib` and `:acldns` (in any order), then the Allegro CL DNS functionality is used first and then, if that fails, the C library functions are used.

Before calling an Allegro CL DNS function, a check is made to see if the Allegro CL DNS module has been configured. If it hasn't been, then `(configure-dns :auto t)` is done (see configure-dns). If this auto configuration fails to find any nameservers then `*dns-mode*` is set to `:clib` so that there will be no further attempts to use the Allegro CL DNS module.

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) 1998-2022, Franz Inc. Lafayette, CA., USA. All rights reserved.
This page was not revised from the 10.0 page.
Created 2019.8.20.

|  | ToC | DocOverview | CGDoc | RelNotes | FAQ | Index | PermutedIndex
| Allegro CL version 10.1 Unrevised from 10.0 to 10.1. 10.0 version