"Invalid command order" error generally occurs after upgrading Apache 2.2 to Apache 2.4 in Zabbix.
Zabbix is an free to use open-source monitoring software tool meant for diverse IT components, including networks, servers, virtual machines and cloud services.
Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to troubleshoot Zabbix related issues.
In this context, we shall look into what causes this error and how to get rid of it quickly.
What triggers Zabbix error "Invalid command order"?
Basically, limit to access of directories API, conf, and include files can be implemented by means of the .htaccess file which is available in Zabbix.
Also, Apache web server version 2.4 have a different syntax when compared with Apache 2.2.
In the process of running Zabbix 2.2.1 or any other older versions on Apache 2.4, you might experience the error message shown below;
Invalid command ‘Order’, perhaps misspelled or defined by a module not included in the server configuration
This is in relation to the change in the configuration specification of the "allow & deny rules".
How to fix Zabbix error "Invalid command order"
As earlier stated, this error occurs as a result of using an outdated version of Zabbix. Therefore, it by using an outdated syntax in the Apache configuration file, Apache will fail to start.
To solve this issue, you can either upgrade to Zabbix 2.2.2 or enable the Apache mod_access_compat module.
You will experience this error when you upgrade Apache 2.2 to Apache 2.4, because there was a change in the configuration specification of the “allow & deny rules”. So ensure that you implement the following rules in the Apache configuration file;
In version 2.2, add the following lines;
Order allow, deny
Allow from all
In version 2.4, add the following line;
Require all granted
Otherwise, you need to enable the below modules to work with “authentication” with the following lines as shown below;
LoadModule access_compat_module modules/mod_access_compat.so
LoadModule authz_host_module modules/mod_authz_host.so
Now the problem will be fixed.