At the hostname and passwords screen (about half-way down), he suggests usings a short name like FW or FireWall. This is a mistake. In order for email, VPNs, AD-SSO and other items to be easy to configure and uncomplicated, it is essential that the hostname be, as the documentation explicitly says, an FQDN that is resolvable by public name servers.
For yourdomain.com, if you had a mail server, we would assign the FQDN used in your highest-priority MX record, and assign the IP as the primary IP on the External interface; that would likely yield a hostname of mail.yourdomain.com. If you don't run your own mail domain, we might assign a hostname of astaro.yourdomain.com and add an A-Record for it to your public authoritative name server.
In fact, if you only recently installed your Astaro and didn't use an FQDN for the hostname, I recommend starting over from scratch... it will be the easiest thing to do in the long run.
At the hostname and passwords screen (about half-way down), he suggests usings a short name like FW or FireWall. This is a mistake. In order for email, VPNs, AD-SSO and other items to be easy to configure and uncomplicated, it is essential that the hostname be, as the documentation explicitly says, an FQDN that is resolvable by public name servers.
For yourdomain.com, if you had a mail server, we would assign the FQDN used in your highest-priority MX record, and assign the IP as the primary IP on the External interface; that would likely yield a hostname of mail.yourdomain.com. If you don't run your own mail domain, we might assign a hostname of astaro.yourdomain.com and add an A-Record for it to your public authoritative name server.
In fact, if you only recently installed your Astaro and didn't use an FQDN for the hostname, I recommend starting over from scratch... it will be the easiest thing to do in the long run.