Nothing actually uses classful networking anymore. Any situation where classful network concepts are implemented is necessarily limiting the capabilities of the network. As such it’s completely useless to bother spending time learning it.
There’s nothing inherently important to classful networking you learn that’s necessary for VLSM. They amount to common convention based on subnet size, and even then nearly nobody actually uses A or B sized subnets except as summary routes, which again, is not inherent to classful networking.
Classful networking has been obsolete for thirty years for good reason, you gain nothing from restricting yourself in that way.
Classful networking is well past dead, that’s kinda pointless. Learn VLSM and general subnetting basics instead.
Dc-Dc is pretty efficient, I wouldn’t worry about conversion after the initial 48v, but I would potentially worry about losses in poor quality home wiring on longer runs in bigger homes
Also if the pfsense router is where the WAN IP lives as might be the case in simpler setups where it is the wan router, it would just note that “hey thats me” and resolve unless there were specific rules preventing that traffic.
Running gaming in a vm isn’t so much a problem either pass through as it is cheat detection may notice and flag you.
Unless specifically stated, generally fiber transceivers only run at the stated rate and would expect every channel to negotiate unless it had a 4x10 mode supported by both the transceiver and the device you put it in (which is what that DAC splitter is for), though once you split the lanes this way, a single pair would only ever run at 10g
Additionally the nature of CWDM on a single pair means the 10g side will see all four signals simultaneously as there are no filters on that side of the connection. QSFP+ runs like this because it’s cheaper to manufacture and a single transmit/receive pair is only necessary in much longer range transport which typically uses more specialized expensive hardware for better long range signal integrity.
In short: no, this won’t work and transceivers generally only ever run in one mode et once as configure by the switch/router they’re inserted in, and the modes you’re asking a qsfp+ to run in are mutually exclusive based on type (single lc pair cwdm at 40g vs 4x10g MPO/MTP with changeable modes). Fiber doesn’t have the same “negotiation” features that copper Ethernet does.
It’s ok I wasn’t using that soul anyway
Number of users total isn’t a big deal, number of concurrent users is. If nobody’s accessing them often it’s not particularly hard on your hardware either
The whole point of 2.5 and 5 is to support higher speeds over existing lower-rated cabling so I don’t see the point of multigig fiber connections when 10g fiber runs on the same cables that 1g fiber does
They make make it but it seems silly.
Starting with a consumer NAS is a good spot, they come with a lot of upfront features that are designed to be easier to use for someone who isn’t already familiar with them. I have a synology and it did all the things you describe without issue (other than struggling with transcoding video in real time) and eventually graduated the heavier tasks like media and proper VM hosting to external secondhand mini PCs while still using the NAS as a network drive to store the data. The NAS itself includes docker and an easy to use repository browser that I use for things like pinhole or WLAN controller software, it has an onboard torrent client (which can use RSS and regex to automate downloads), and it has some other light hosting services, which it’s quite capable of. Starting with “just” the NAS and adding external devices as your use case shifts is always an option. Keep in mind that the best way of upgrading a NAS’ storage is leaving a bay open and upgrading disks one by one without having it do a “hard” rebuild from parity data, so 4 bays at least is a good starting point.
If you want to start with just an off the shelf NAS as an all in one device I would recommend making sure it either has or can take additional RAM (no such thing as too much), an NVME cache (more optional but nice) and an intel processor (quicksync transcoding, though the low end cpus will definitely still struggle with trying to turn 4K into 1080 for a stream). I’d be willing to bet most of the consumer NAS devices will all support docker at this point and have similar built in feature sets. Some of the newer models will support onboard 2.5gbe which is nice but probably unnecessary for a single user or family.
External access would be more of a job for your router/firewall which would use PAT to forward connections to your internal network, so that’s outside the scope of your NAS unless you’re building a true all in one box that acts as the central hub of your entire home network.