While many things in the frontend can be configured using the frontend itself, some customisations are currently only possible by editing a definitions file.
This file is
defines.inc.php located in /include of the Zabbix HTML document directory.
Parameters in this file that could be of interest to users:
Number of unsuccessful login attempts that is allowed to an existing system user before a login block in applied (see ZBX_LOGIN_BLOCK). By default 5 attempts. Once the set number of login attempts is tried unsuccessfully, each additional unsuccessful attempt results in a login block. Used with internal authentication only.
Number of seconds for blocking a user from accessing Zabbix frontend after a number of unsuccessful login attempts (see ZBX_LOGIN_ATTEMPTS). By default 30 seconds. Used with internal authentication only.
Default graph period, in seconds. One hour by default.
Minimum graph period, in seconds. One minute by default.
Maximum graph period, in seconds. Two years by default since 1.6.7, one year before that.
The maximum period to display history data in Latest data, Overview pages and Data overview screen element in seconds. By default set to 86400 seconds (24 hours). Unlimited period, if set to 0 seconds.
Default location of Y axis in simple graphs and default value for drop down box when adding items to custom graphs. Possible values: 0 - left, 1 - right.
Controls how many issues are shown in the dashboard's Last n issues widget. By default 20 issues are shown.
Used in screens and defines the timeout seconds for a screen element update. When the defined number of seconds after launching an update pass and the screen element has still not been updated, the screen element will be darkened.
Used in screens and defines the number of seconds after which query skipping will be switched off. Otherwise, if a screen element is in update status all queries on update are skipped until a response is received. With this parameter in use, another update query might be sent after N seconds without having to wait for the response to the first one.
Defines retrieval limit of the total items queued. Since Zabbix 3.2.4 may be set higher than default value.
Validate a URI against the scheme whitelist defined in ZBX_URI_VALID_SCHEMES.
A comma-separated list of allowed URI schemes. Affects all places in the frontend where URIs are used, for example, in map element URLs.
Show technical errors (PHP/SQL) to non-Zabbix Super admin users and to users that are not part of user groups with debug mode enabled.