1/* Domain name validation.
2   Copyright (C) 2006, 2007, 2008, 2009, 2010 Jan Rafaj
3
4   This program is free software; you can redistribute it and/or modify
5   it under the terms of the GNU General Public License as published by
6   the Free Software Foundation; either version 3, or (at your option)
7   any later version.
8
9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
16
17module 'valid_domain'.
18require 'dns'
19
20#  boolean valid_domain (string DOMAIN)
21#
22# Returns true if the domain name DOMAIN has a
23# corresponding A record or if it has any MX records, that is if it can
24# be possible to send mail to it.
25#
26func valid_domain(string domain)
27  returns number
28do
29  return not (resolve(domain) = "0" and not hasmx(domain))
30done
31