ysjet

You do realize your DNS MX records can point to both IPs, and your primary connection just has a higher priority number, right? This is 2025, dns is outright expected to have multiple IPs behind in varying levels of priority and availability. As for DDNS constantly rolling things, I’ve got, as I said, spectrum residential and my IP address has changed once in half a decade. Finally, I literally mentioned that there were other ways around this, like an external proxy server on a static IP. Throw it on DO or something.

That is, in fact, exactly the opposite of what I just said.

I would actually disagree- it doesn’t take much budget at all, or even a quality server setup, to have a decent uptime. A consumer router with a sim card slot is possibly something you already have. If not, a cell modem can be as cheap as $30. You could stick your email server on a old shitty raspberry pi. A data sim is $6/mo. If all you’re running is a cable modem, a router, and a rpi, you don’t even need a big fancy UPS, you can just get a DC battery UPS for like $40. It doesn’t need a lot of budget, quality stuff, or even a ton of hours in the week for self hosting- once you get this stuff set up it should stay working other than the standard upgrades/maint your email server will need. Everything past that, like setting things up so your mail server is reachable on two IP addresses, is just… skill.

So this sort of a setup is called Dual-WAN, and yes, it allows it all to work. Basically, my router has two connections to the internet- a cable modem on one port, which connects to Spectrum, and a cell modem on another port, which has my sim card on it. Both provide internet access simultaneously. My router is then configured to reach the internet via what it decides is the ‘best’ internet. In my case, because my cell connection is metered, I have it configured so that it prefers the spectrum connection, and only falls back to the cell connection if the spectrum connection is losing traffic, and only for as long as that connection is losing traffic. Note that a dedicated cell modem is not necessarily required- some routers have sim card slots themselves, for exactly this reason, and tend to make this sort of configuration very simple to do. I’m personally using a small computer running OPNSense, which is again, probably overkill for the average homelabber, but you don’t need something that complicated. As a result, my server always has access to the internet, and should you configure your firewalls appropriately, the internet will then always have access to your server. There’s some details here and there about IP address caching, dns resolution, and the like which have various solutions from DDNS to an external proxy/loadbalancer/etc, but those are more implementation details.

I mean, my use case is abnormal and generally has more beef behind it than most people would have, yes, but a simpler, cheaper version of what I have set up is kind of a no-brainer if you want to self-host. e.g. I don’t think a simple cyberpower/APC ups on your home server is any kind of a weird ‘specialty’ thing, and it should definitely run your server for 2-3 hours during an outage for like $100-150 if you grab it on sale (which, you know, why wouldn’t you?) As for the generator, I don’t have that for my network stack, I have that for my fridge/deep freeze lol. It can just also recharge my UPS if it’s really that big of a deal. As for cell backup, that’s definitely less a ‘common’ homeserver thing, but I’m only paying like $14/mo for my cell backup connection from tello for 5gb of 5G. Hardly breaking the bank, and honestly probably overkill, you could likely get away with their $10/mo 2gb plan. No complaints with it either, I use them for my regular cell plan too. if you were interesting in self-hosting your own email server and wanted better uptime than 99.9%, you probably don’t even need that if your ISP only sucks slightly instead of mostly, but it allows you to just not care about your ISP having extended downtime.

Your ISP is kind of dogshit if it’s forcing 15-30m of downtime overnight every few weeks. And power outages are kind of a weird thing to focus on, you should be on a UPS anyway. In any case, someone interested in self-hosting email very likely has a redundant connection anyway. I’m not even hosting my own email and I have 5gb/mo of cellular backup in dual-WAN, and enough battery capacity to run my entire stack for several hours. Not to mention a generator to recharge them, if it comes down to that.