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8 Known issues

Problems with pressing Enter in configuration forms

Affects Zabbix versions 3.0.0 - 3.0.4. Pressing Enter in a text field of a configuration form is known to result in various problems.

For instance, if you open the configuration form of a host with linked templates, then press Enter in any text field and update the form, template linkage is removed (items from the template remain).

Agent items

  • net.dns[] Zabbix agent item does not support IPv6 addresses in its first parameter.

IPMI checks

IPMI checks will not work with the standard OpenIPMI library package on Debian prior to 9 (stretch) and Ubuntu prior to 16.04 (xenial). To fix that, recompile OpenIPMI library with OpenSSL enabled as discussed in ZBX-6139.

SSH checks

Some Linux distributions like Debian, Ubuntu do not support encrypted private keys (with passphrase) if the libssh2 library is installed from packages. Please see ZBX-4850 for more details.

ODBC checks

Zabbix server or proxy that uses MySQL as its database may or may not work correctly with MySQL ODBC library due to an upstream bug. Please see ZBX-7665 for more information and available workarounds.

HTTPS checks

Web scenarios using the https protocol and Zabbix agent checks net.tcp.service[https…] and net.tcp.service.perf[https…] may fail if the target server is configured to disallow TLS v1.0 protocol or below. Please see ZBX-9879 for more information and available workarounds.

Simple checks

There is a bug in fping versions earlier than v3.10 that mishandles duplicate echo replay packets. This may cause unexpected results for icmpping, icmppingloss, icmppingsec items. It is recommended to use the latest version of fping. Please see ZBX-11726 for more details.

SNMP checks

If the OpenBSD operating system is used, a use-after-free bug in the Net-SNMP library up to the 5.7.3 version can cause a crash of Zabbix server if the SourceIP parameter is set in the Zabbix server configuration file. As a workaround, please do not set the SourceIP parameter. The same problem applies also for Linux, but it does not cause Zabbix server to stop working. A local patch for the net-snmp package on OpenBSD was applied and will be released with OpenBSD 6.3.

Web monitoring

Zabbix server leaks memory on CentOS 6, CentOS 7 and possibly other related Linux distributions due to an upstream bug when “SSL verify peer” is enabled in web scenarios. Please see ZBX-10486 for more information and available workarounds.

Compatibility issue with PHP 7.0

It has been observed that with PHP 7.0 importing a template with web monitoring triggers may fail due to incorrectly added double quotes to the web monitoring items in the trigger expressions. The issue goes away when upgrading PHP to 7.1.


Changes to Daylight Saving Time (DST) result in irregularities when displaying X axis labels (date duplication, date missing, etc).

Non-ASCII characters are incorrectly saved in MySQL

Affects Zabbix versions 3.0.0, 3.0.1 and 3.0.2 using MySQL database. Issue occurs when Zabbix server or proxy reads, processes and saves back to the database text containing non-ASCII characters (automatic template linking, low-level discovery, notification messages, …) The issue is transient, it is related to MySQL automatic reconnection behaviour. Fixed in 3.0.3rc1, ZBX-10540 contains patch and more information on the issue.

Log file monitoring

log[] and logrt[] items repeatedly reread log file from the beginning if file system is 100% full and the log file is being appended (see ZBX-10884 for more information).

Slow MySQL queries

Zabbix server generates slow select queries in case of non-existing values for items. This is caused by a known issue in MySQL 5.6/5.7 versions. A workaround to this is disabling the index_condition_pushdown optimizer in MySQL. For an extended discussion, see ZBX-10652.

API fails decoding valid JSON-RPC request

Affects Zabbix versions 3.0.4, 3.0.5. API fails to decode a valid JSON-RPC request unless a non-requirement php-json module is installed. ZBX-11244 contains more information on this issue.


Several operations can be assigned to the same step. If these operations have different step duration defined, the shortest one is taken into account and applied to the step. But due to bug there was exception to this rule when step duration is set to 0, it would use default value instead of shortest one. Now there will be no exception and default step duration will only be used if it's shortest, this is equivalent to behavior that frontend shows and user expects. Affects all versions, fixed in 3.0.7rc1, (see ZBX-11534 for more information).


The output parameter does not work properly with the history.get method.

API login

A large number of open user sessions can be created when using custom scripts with the user.login method without a following user.logout.

IPv6 address issue in SNMPv3 traps

Due to a net-snmp bug, IPv6 address may not be correctly displayed when using SNMPv3 in SNMP traps. For more details and a possible workaround, see ZBX-14541.

Known issues for 3.0.0 - 3.0.17

  • Remote commands executed on Zabbix server are displayed with an initial : colon in ReportsAction log.

Known issues for 3.0.0 - 3.0.18

  • When proc.mem, proc.num agent items are invoked from the command line and contain a command line parameter (e.g. using the agent test mode: zabbix_agentd -t proc.num[,,,apache2]), two extra processes are counted, as the agent counts itself twice.

Known issues for 3.0.18

  • 3.0.18 version Zabbix servers are not backwards (or forwards) compatible with 3.0.x proxies. Fixed for 3.0.19 Zabbix server.

Known issues for 3.0.0 - 3.0.24

Known issues starting with 3.0.25

  • Failed login attempt message has been changed to display only the first 39 characters of a stored IP address as that's the character limit in the database field. That means that IPv6 IP addresses longer than 39 characters will be shown incompletely.