I have 2 questions I’m looking to confirm. The first being is it alright to host a blog and mail server on the same server? I currently have my blog up (dynamic site) and was looking to setup mail hosting, but I know some things don’t like being hosted together and cause issues.
My second question is related to DNS, I know mailinabox is using NSD, but can I use the name servers as my personal DNS server? Because I was looking to set one up, but not sure if it’s dedicated to mailinabox.
The general answer to this is yes, BUT the answer to this when using MiaB is generally no. MiaB is designed to be a stand alone mail and dns solution for your domains. It is recommended that websites be hosted elsewhere with the exception of the simplest of static sites. So the answer in your case is that you could host mail on the server that you are hosting the blog, but the mail solution cannot be MiaB in that case.
Yes, MiaB is an ideal solution for hosting DNS for your domains. There are some quirks but they are minor.
Everything in server considerations can be answered with one word: depends. For the most part, it is not really a good idea to put a mail server and web server on the same server or vm. Primarily because mail is something that is generally desired to be available at all times, and your web server likely will run various more buggy and vulnerable software or experience periods of exceptionally high traffic that may, from time to time, knock the server offline.
You can, but do you really want to? This will mean that all servers using the DNS server will be unavailable if the MiaB server is offline, for whatever reason. There are very easy to use and free DNS servers that properly follow the published standards, which includes things like redundancy and physically separate failovers using distinct connections to the Internet. Personally, I use Namecheap because their domain registration prices are as low as anyone and they offer free DNS plus free DDNS and they support DNSSEC. I’ve never had any real problems with them, though they still don’t offer CAA records (not yet a genuine issue).