Having a weird issue on my network now (Frontier Fios if that matters), and the only change to the network has been me updating my Mac mini 2018 to Big Sur last week. Im hoping its Big Sur, otherwise I got something serious going on here. Maybe Frontier flipped a switch or something this weekend?
I have a couple of ports forwarded in my router at home and noticed my Mac wasn't communicating properly last night. I logged into the router and noticed my Mac (along with a bunch of other devices, mainly everyones iPhones and iPads) all had two entries in the DHCP table. Each one had an IP address with its actual hardware MAC listed, and then about 2 minutes after signing in, another one will pop up with a new address, but the MAC now starts with 8A:41:FC and the last three numbers are from the actual MAC address. Looking in the network prefs, my Mac still shows its actual hardware address, but now my IP is the one that's pointing to the 8A:41:FC version in the router. I cant set port forwarding, I cant reserve DHCP addresses nothing, because if I set it to one, occasionally it will bounce back and forth between the addresses and none of my services point to the right computer. I cant even make a DHCP entry for our canon printer because even it was doing the same thing. The odd part is, its not just the Apple stuff, there are quite a few devices that are doing this (my Xbox and Switch did it as well). At first I was thinking I had some internet sharing on by default and my Mac was being the gateway but nope, this stuff is all off, no sharing of anything whatsoever.
The ONLY change that's been made here has been me updating to Big Sur, but I didn't notice this right away last week so it may not have popped up until this past weekend, Im not exactly sure. Last night while troubleshooting, I shut the Mac mini's wifi off, rebooted the router, and then signed into it from my iPhone (running iOS 13).. Everything was fine until the minute I turned the Mini on, and those new duplicate reservations started popping up. Even reset the router to defaults and started from scratch, those fake addresses were there from the minute stuff started connecting.. Frontier just upgraded this router like 2-3 weeks ago (they bumped us up to gigabit) and it was perfectly fine when I initially setup port forwarding the day the tech was here. Our kid got one of those Airi extenders, but that's been in place since before we were even upgraded to the gigabit connection and its never done anything other than let him connect in his room.
I have a couple of ports forwarded in my router at home and noticed my Mac wasn't communicating properly last night. I logged into the router and noticed my Mac (along with a bunch of other devices, mainly everyones iPhones and iPads) all had two entries in the DHCP table. Each one had an IP address with its actual hardware MAC listed, and then about 2 minutes after signing in, another one will pop up with a new address, but the MAC now starts with 8A:41:FC and the last three numbers are from the actual MAC address. Looking in the network prefs, my Mac still shows its actual hardware address, but now my IP is the one that's pointing to the 8A:41:FC version in the router. I cant set port forwarding, I cant reserve DHCP addresses nothing, because if I set it to one, occasionally it will bounce back and forth between the addresses and none of my services point to the right computer. I cant even make a DHCP entry for our canon printer because even it was doing the same thing. The odd part is, its not just the Apple stuff, there are quite a few devices that are doing this (my Xbox and Switch did it as well). At first I was thinking I had some internet sharing on by default and my Mac was being the gateway but nope, this stuff is all off, no sharing of anything whatsoever.
The ONLY change that's been made here has been me updating to Big Sur, but I didn't notice this right away last week so it may not have popped up until this past weekend, Im not exactly sure. Last night while troubleshooting, I shut the Mac mini's wifi off, rebooted the router, and then signed into it from my iPhone (running iOS 13).. Everything was fine until the minute I turned the Mini on, and those new duplicate reservations started popping up. Even reset the router to defaults and started from scratch, those fake addresses were there from the minute stuff started connecting.. Frontier just upgraded this router like 2-3 weeks ago (they bumped us up to gigabit) and it was perfectly fine when I initially setup port forwarding the day the tech was here. Our kid got one of those Airi extenders, but that's been in place since before we were even upgraded to the gigabit connection and its never done anything other than let him connect in his room.
