A while back we've had a couple extended downtimes caused by the router crashing and requiring a hard reboot. I've just gotten a response from my ISP that they in their testing also discovered the router was acting a bit weirdly, so they're sending me a replacement router.
I will post again once I receive it to plan for the downtime when I swap the two (likely an hour or less).
Planning to do the router exchange in about an hour
Edit: when I start, the plan is that I take the old router out, put the new one in, which I've already mostly configured to be correct. Some parts of it I couldn't do beforehand, but if all those go smoothly the total downtime should be less than 15 minutes. If there are problems there might be up to an hour downtime. If there's more than that I'll just roll back to the old router since then there's a serious problem heh.
Update: the router config somehow reset once I moved it, and even once I readded the NAT mappings I'm having problems getting it to work properly. Estimate is now closer to an hour. Hopefully I will figure it out.
I was unable to get the new router to work properly and have reverted to the old one. I may need to take additional downtime tomorrow when my ISP's support is also available.
I'm planning to again take server down later today, with my ISP support on the line to help me while I do. Downtime will start around 7 hours from now, I'll post warnings when closer to that time. I'd expect an hour downtime or so.
turns out the problem was out of 4 ports on the router, where I was told by the ISP not to use port 4, port 1 didn't work properly. Once I moved to port 2 everything seemingly works fine. Don't ask me why.