Zabbix is free software, released under the GNU General Public License (GPL) version 2. You can redistribute it and/or modify it under the terms of the GNU GPL as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The formal terms of the GPL can be found at http://www.fsf.org/licenses/ . This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. Exception for linking with OpenSSL In addition, as a special exception, we give permission to link the code of Zabbix with the OpenSSL project OpenSSL library (or with modified versions of it that use the same license as the OpenSSL library), and distribute the linked executables. Please see http://www.zabbix.com/ for detailed information about Zabbix. On-line Zabbix documentation is available at http://www.zabbix.com/documentation/4.0/manual/installation/install .