You probably don't get enough of these, so I'll offer one. My main home server is a Sun T5240 (also makes a nice supplementary heat source in winter; yes, it is a bit much for home, but I used to work with similar but larger systems, so call it nostalgia). One of a number of things it does is run a DHCP server, specifically ISC DHCPD. Without the DHCP server running, it's not long before various gadgetry not capable of static configuration gets flaky or unreachable. (home routers can do DHCP, but not configurable, so they won't hand out reserved IP addresses corresponding to specific MAC addresses...which makes e.g. Xymon monitoring a LOT easier than with a bunch of constantly changing addresses)
Another server I have is a Mac mini, which mainly runs a VPN server to allow me remote access, and ServeToMe to stream movies and TV show collections to me wherever I may be, if I wish; and occasionally, some VMs. Since it draws MUCH less power than the T5240, it's feasible to have it and its nearest Ethernet switch on a small UPS (my router, modem, and other Ethernet switch are on another UPS, in another room). Now and again I have to shut the T5240 down for reconfiguration, or because I'm doing something on that circuit and have to pull the breaker. Macs have a DHCP server of sorts, but different and not as flexible as the ISC one. And the ISC one can do failover! It totally made my day that MacPorts had a well working port of the ISC DHCP server; all I had to do was read up on the additional config file content needed for failover, install that, uncomment the portion meant for the secondary in the copy for it, create the leases file per the port notes, and "port load dhcp". Something that seemed at first like it might take me hours to get working took more like half an hour, mostly RTFM'ing. Boom, failover working, now I can fool around without having to cope with a house full of crazy gadgets! Thanks... PS yes, I could make the default leases a lot longer, but that'd make changes taking full effect a lot slower, too. PPS I probably need an UPS for at least one HomePod too, since they act as HomeKit hubs. And I need to put the Hue hub, near the Mac mini anyway, on the UPS too. I keep trying to move things toward being a bit more robust...
