Technical Tip: Time zone Information tz="+0000" is missing in the FortiGate Logs when the time zone is set to GMT (UTC)

The time zone information is included in the logs by default, as shown below.

date=2025-07-10 time=02:05:29 eventtime=17521131291387xxxxx tz="+0000" logid="0001000014" type="traffic" subtype="local" level="notice" vd="root" srcip=10.56.240.8 srcport=12826 srcintf="root" srcintfrole="undefined" dstip=173.243.xxx.xx dstport=443 dstintf="port1" dstintfrole="undefined" srccountry="Reserved" dstcountry="Canada" sessionid=508 proto=6 action="server-rst" policyid=0 service="HTTPS" trandisp="noop" app="HTTPS" duration=6 sentbyte=5172 rcvdbyte=10078 sentpkt=15 rcvdpkt=15 appcat="unscanned"

However, after upgrading to FortiOS patch 7.4.7 build 2731 and above, the time zone information 'tz="+0000"' is missing in the FortiGate logs when the time zone is set to GMT (UTC), as shown below.

config system global
    set timezone "UTC"
end

In the example log, the time zone information is missing.

date=2025-07-10 time=02:18:17 eventtime=17521138982076xxxxx logid="0001000014" type="traffic" subtype="local" level="notice" vd="root" srcip=10.56.240.8 srcport=19934 srcintf="root" srcintfrole="undefined" dstip=10.56.240.1 dstport=514 dstintf="port1" dstintfrole="undefined" srccountry="Reserved" dstcountry="Reserved" sessionid=481 proto=6 action="timeout" policyid=0 service="RSH" trandisp="noop" app="RSH" duration=13 sentbyte=180 rcvdbyte=0 sentpkt=3 rcvdpkt=0

The known issue (ID: 1180038) is reported when the FortiGate is configured with UTC, which causes the time zone information tz='+0000' to be missing from the logs. This issue will be resolved in an upcoming FortiOS release. Monitor Known Issue ID 1180038 in the release notes under the 'Resolved Issues' section.

As a workaround, configure a different time zone instead of UTC and then change it back to UTC.

config system global

       set timezone "Etc/GMT+12"
end

config system global
     set timezone "UTC"
end

However, once the FortiGate is rebooted, the workaround will need to be applied again.
The automation stitches can be configured to automatically apply the workaround configuration after a reboot, See Technical Tip: How to configure Automation Stitch to trigger after the FortiGate reboots.