I’m in the process of setting up a dedicated server which will host multiple virtual servers but I’m new to this so would appreciate a bit of help. I’ve got my primary domain pointing at the server and as I understand it need to use something like xyz.domain.com as my hostname, so that could be something.primarydomain.com, correct?
Secondly, multiple clients will use my server for email. Rather than getting them to use mail.client1.com, mail.client2.com, etc. I figured it’d be best to get an SSL cert for my primary domain and get them to connect to that instead. Does that seem reasonable? If so, would using my hostname as the mail server address be OK or would it be better to use something like mail.primarydomain.com?
That is the convention, yes. Most people either use something like web01, or some kind of naming scheme like starwars characters or mythological figures. In the end it doesn’t really matter all that much, but I would suggest you take a name that makes it easy to add more later. For example with www, a next server would be, what, www2? Doesn’t have a nice ring to it.
There are no rules to this, just pick something you’re comfortable with.
Seems totally reasonable to me, as long as the clients know they are connecting to your server and the hosting name doesn’t come as a surprise to them (i.e., “Why would I connect to this host I don’t know for my email?”).
It makes it clear that you are connecting to a server to fetch email. Even though [noparse]www.example.com[/noparse] would work just fine, it may seem strange to people and lead to questions and debates that are completely useless (and probably annoying too)
If you ever find that your server is under high load and wish to scale it, you can easily put your mail on a new server using the same [noparse]mail.example.com[/noparse] while you keep your [noparse]www.example.com[/noparse] on the old server (or the other way around of course).
So, you don’t have to use a name like [noparse]mail.example.com[/noparse], but it certainly is advisable to do so.
You must set up SPF records per domain, and make sure your server is allowed to send email for them.
(SPF records are based on the domain of the email of the sender, not on the domain that sent the email).
One last question about rDNS: I have domains and hosting handled by different companies so who would set up the rDNS record; the domain company or the hosting company?