Where are you seeing the timezone incorrectly set?
Since you mention 3 timezones, I assume you have clients covering different timezones and they are seeing this when reading email?
If this is the case it’s not really a server issue, more a mail client issue (and a common one at that).
As for changing the timezone on the server, it shouldn’t present any issues. Just do a reboot of the server after changing the zone so that all the services can start up with the correct timezone loaded.
Personally I always go with UTC, making it easier to search through logs on multiple servers.
Huh? The timezone shown in the terminal is ultimately the one that the server is set to…
Webmin also shows correctly (at least with UTC).
Could you share the output from terminal and screenshot of Webmin, showing what you mean?
As mentioned, I have updated on an active mailserver before without any issues.
Maybe I’m missing something but I thought the timezone setting on a device affects only the time display on that device.
Therefore changing the timezone on a server shouldn’t change anything on a client device.
The most common mistake I’ve seen is to set the time on a device (e.g. the server) to the wall clock local time but leave the timezone at some default (e.g. UTC or UTC-8). Clearly this will set the wrong TIME on the device unless you happen to be on that timezone.
SSL and similar time issues are because the absolute time is incorrect, not the timezone.
It’s really important that the time and timezone together compute to the real, absolute time.
Also check that if the device sets the time from an external source on reboot, that the result is going to be correct.
Just to reiterate a point, you’ll notice that configuring a timeserver (e.g. ntp.org) does not require you to know the timezone. NTP will give you the absolute time and your local device timezone settings will determine the time displayed.
We are using Roundcube - so the device is actually hosted on the server - we have Roundcube mail scheduler installed …
This is what created a somewhat confusing environment for users. Server Timezone, users on a different local timezone, scheduling mail to be sent to target audience in 3rd timezone .
Although Roundcube runs on your server, the timezone settings are determined by the client or user.
Each Roundcube user can set their timezone in Settings>User interface.
This post (from 2013) (Wrong time is shown in message view. · Issue #4155 · roundcube/roundcubemail · GitHub) explains Timezone=Auto like this
I’m not familiar with Roundcube Mail Scheduler but I would first make sure the clients are using the expected (or required) timezone. I’m not sure how to do that but I’d start by checking the send and receive times on a test email.
This is a quote from Roundcube support
When you schedule a message, the plugin always uses the server’s date/time when it saves the record into the database. This is done because the cron job that runs on the server and triggers the message-sending function runs independently of any user account, so it doesn’t take into account the user time zones at all. When running, the sending function simply takes the current time and retrieves from the database the messages that have been scheduled to be sent on this exact minute (scheduled using the same date/time function as is used to retrieve them.)
In a nut shell ( My Question really was - can I update my mail servers timezone with disrupting mail delivery )
All the best