A few of my site's users have mentioned that they are not receiving site critical emails, such as password reminders, activation emails etc. Some of the emails are being bounced back to the email address they were originally sent from. I don't have the actual error that the email contains, but it is related to the hostname of the server. It's a dedicated server, and the hostname is <myusername>.localhost.localdomain. The email errors are reporting that this is (obviously) not a valid host. I have absolutely no idea how to change this. I have had a quick look in the DNS settings within Webmin although there seems to be no visible way to change this. So, does anyone know how I can change the server's hostname to something that is actually perceived as valid?