Email alias AND keep locally

Is it possible to set up an email inbox that also forwards to an external email.
So someone can see emails in their gmail account but can login to my mailinabox and reply later.

I tried a mailbox + alias and it forwarded but the email never arrived in the mailbox itself.

If you add a user and also add an alias with the same user name it will arrive in the mailbox itself.

If you’ve set it up correctly that is. You need to forward to two desitinations, the local user and the gmail user. It sounds like you may have missed this part.

But regardless — YOU DO NOT want to forward email to an external email address as it will not be reliable. Especially if you are forwarding to Google.

Use Google Mail Fetch instead … or use a filter in Roundcube.

Thanks I found the filters just a minute ago and used the forward a copy option.
So hopefully that is the right answer