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Spam and virus filtering in the Classic Linux environment is done in two different places.
First, when incoming mail arrives via SMTP, any mail that either contains a clearly identifiable virus (as diagnosed by clamd), or is spam with a high degree of certainty (as diagnosed by rspamd), is immediately rejected and never accepted. The sender will get a bounce explaining why the email was rejected. This is not under user control.
Second, any mail that is accepted, which might or might not be spam, is spam-filtered via SpamAssassin. This is under control of the user, and can be switched on or off via the Virtualmin control panel.
If you go to the menu:
Virtualmin ⇒ Server Configuration ⇒ Spam and Virus delivery
you can see which folders are configured by default to receive spam and viruses. (You can also change these if you want to, but please exercise great caution, and make a screenshot before you make changes. Then you can restore any changes if needed.)
These spam and virus folders will be automatically created as soon as your first spam or virus is received.
Roundcube webmail might not automatically show you the spam and virus folders. To make them visible, please do the following.
There is a little icon near the top of the screen, a little to the right of your email address, that looks like three dots, vertically stacked. (It looks like this ⋮ on devices with the right fonts.) Clicking on this will give you a pop-up menu from which you can click on Manage folders. Now you can enable or disable the folders you want to see, including the spam and virus folders.
To actually access mail in these folders, click on the Mail icon at the left, then on a folder.
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