Access mac file server remotely
I have a 2012 mac mini, that I have made into my file server. But I am wanting to be able to access my files remotely. Is there a good way to do this. I want to access it from my Macbook Air(M2).
Earlier Mac models
You could simply create a port forward through your router/firewall for the file service(s) ports that you are using (548 for AFP or 445 for SMB). However, this is a very risky solution as you are opening those ports up to potential exploit by malicious scanners or bots. The SMB protocol is heavily attacked so opening that port to the world is not recommended.
Ideally, you would implement a VPN. The VPN will allow you to securely connect to the environment that has your server. Once connected to the VPN, you would then connect to your file server as if you were on the LAN. The VPN creates a secure tunnel to your server LAN. However, Apple's Server.app dropped the VPN ages ago and if you don't have a true firewall appliance, you likely do not have a VPN service readily available.
Ah, but this is further complicated (maybe) by the type of internet service you have at the server's location. If you are on a residential service, you likely have a dynamic IP address. Your ISP can change that address at any time. This makes remote access challenging as the target keeps changing. This can be solve by setting up a Dynamic DNS service on your LAN with the server. That will keep up with the changes from your ISP. But this adds complexity that you may not want.
As an alternative, have you looked at cloud file service solutions? I guess the first questions are, how many people are going to use this data (are you doing this for personal use or for business), and how much data do you have?
Consider looking at Microsoft (1 TB personal storage + 1 TB collaborative storage on most licenses), Google, Apple (various pricing tiers), or Dropbox (various pricing tiers) to start. Look for cloud services that support selective file sync as this will allow you to have a larger data set in the cloud than your local hard drive can accommodate. Only the files you recently opened will fully exist locally.
By using a cloud service, you eliminate the need for a server, a local backup, power redundancy, a secure remote access method, worrying about local security, understanding your internet service type, etc. Now your data is with you wherever you are and whenever you need it with no step two.
Hope this is helpful.