If I had it to do over, I would put 2 Ethernet drops on every wall of living space but the bathrooms. And pull strings in every drop. (Conduit to hard ones) You will want a “computer room” for the network stuff, but also NAS, DVR, smart home hub, and more as the needs grow. Dedicated circuit an a place to mound a business class rack mount UPS. (2200 or better) And speaking of power, you should add more than you need. And leave room for monitoring it in the box. If your panel is in the garage, a shelf for another switch may be handy. I have a switch in my house, my detached garage, and my shed…

You want to look for a “dry contact relay” that works with what you have. I got one for Zigbee because I have home assistant with zigbee. This will work in your existing system or in an app or whatever.

You have to understand the priorities of the rack server market.

#1 is dependability. It needs to keep running no matter what. Evenrthing is built around overbuilding it. More cooling, dual CPUs, Dual power supplies, lots of drives in RAID…

#2 is size. Colo space is expensive! So keep it small. So everything is densely packed, which is bad for airflow. And you get stacked small fans running at the speed of sound.

#3 is performance. Yeah, you would think it was first, but it ain’t. But that means 10k and 12k spinning drives. These are loud and noisy!

Way down the list is power… When you consider the cost of the hardware new, the cost of the colo space, and the cost of the people maintaining it, the power cost is next to nothing. The only thing less important than power consumption is sound which is not even on the list…

Now, compare that with workstations. They have a lot of the same components like Xenon CPUs, lots of ram, raid… But they sit on a desk, so noise, heat and power are a real concern. And they are often overlooked in the used and refurb market. So for less money, you get server like components and performance, in a quieter and more power friendly form factor.

More spindles means better performance. But also more power use. Only you can decide which is more important.

The problem with selfhosting email, is that unlike other self hosted things, it lives in a distributed system. It has to talk with other mail servers and they have to talk back. The second part is hard due to spam measures…

For just the software side, you have a few options. Mail cow, iRedmail, and Mailinabox are very popular. Linuxbabe has instruction on how to build it from scratch using postfix. (Good to learn, but a LOT of work) But recently I stumbled on Modoboa. It does not need docker, so you can run it alone. It is not split foss with everything good behind a paywall. And it does not install unneeded apps like DNS for no reason. But keep in mind that I have only evaluated it so far and not yet put it in production.

Now for the other needs… To receive mail, you will need a static IP. Theoretically, you can get by with a dynamic DNS, but it will not go well. Your IP will change, and it will still be cached and you will lose email.

To send mail… (This is a lot more) You will need a clean static IP, with a fqdn and ptr record matching. It will need to be clean, and not in a blocked range of IPs. You will also need SPF and DKIM records, and may need dmarc. And you will need to warm up the mail server and maintain it’s cleanliness. Or you can contract out your outbound to other companies like MXroute. If you farm out your outbound, it eliminates most of the complaints above. If you have the skill, you may be able to only route Microsoft and Google destined email, and direct deliver the rest yourself. (I am working on this)

https://www.ebay.com/itm/254845248977

Cisco Catalyst 2960-X WS-C2960X-48FPD-L 48 Port GigE PoE 2x 10G SFP+ Switch

2 SFP+ ports, and 48 1gig Poe+ ports. A solid switch that has a lot of help and documentation on the web. Also, learning Cisco will not hurt your job options.

Edit: Note that this is cheaply stackable if you need more ports. Yes, that will be a bit power hungry.

A wireless cammera will be more trouble than a wired one, and it will be more trouble than you think. That said, if it supports rtsp, there is a lot of DVR software that will work with it. Blue Iris was mentioned. ISpyConnect also is solid. I use Zoneminder.

I had a client that needed a caching DNS, and I put in pi hole. Did everything they needed, plus diagnostics, and ad filtering. And all with a very easy GUI.

A lot of this will depend on who is going to maintain this. Because there is cheap, fast and easy, but you can only pick two… I will tell you that what you have no is the cheapest crap they think they can get away with. The best way to do this is with a cable modem alone, a solid router with no WiFi, and WiFi access points wired throughout your house. But this is also more complex to manage. The easy way is an Orbi like system where you get an ecosystem based on mesh networking. This will slow you down, add latency, and can be a bear to troubleshoot when something goes wrong.

But the question is what are you willing and able to do?

Worst case is that you lose everything. The only way to protect that is an out of band pull type of backup. One that you servers can not get to or see, but can see your servers. Best at another location as well to protect against fire.

Another vote for Dokuwiki. All flat files, and no db. Also can run as a portable app on Windows, so you can bring it to work on a thumb drive.