Network shows 255 connected devices

[20sidedEric]

I have cable modem service. From the cable modem, an Ethernet cable runs to a TP Link TL SG105 Gigabit Ethernet switch, then two Ethernet cables out. One to my desktop, the other to my wireless router, a Netgear Nighthawk X6 AC3200.
My desktop resides in the 174.XXX.XXX.XXX address space while the router of course resides in the 192.XXX.XXX.XXX address space. As such, I cannot use the netgear utilities to connect to my router to manage my network. Further, when I do connect to the Netgear utilities, the "Attached Devices" option shows 255 connected devices, each with a unique MAC address (or at least as far as the 30 or so I checked). What gives?
Since the switch is "unmanaged", shouldn't it receive its addressing from the router?

 

[kanewolf]

Do you pay for multiple public IP addresses? It is unusual to have a switch plugged into a modem. The ISP usually only provides one public IP address. Whatever device connects to the modem first gets the public IP address.

The typical installation is modem->router-> switch-> devices

An unmanaged switch does not get an IP address.

 

[BuddhaSkoota]

I have cable modem service. From the cable modem, an Ethernet cable runs to a TP Link TL SG105 Gigabit Ethernet switch, then two Ethernet cables out. One to my desktop, the other to my wireless router, a Netgear Nighthawk X6 AC3200.
My desktop resides in the 174.XXX.XXX.XXX address space while the router of course resides in the 192.XXX.XXX.XXX address space. As such, I cannot use the netgear utilities to connect to my router to manage my network. Further, when I do connect to the Netgear utilities, the "Attached Devices" option shows 255 connected devices, each with a unique MAC address (or at least as far as the 30 or so I checked). What gives?
Since the switch is "unmanaged", shouldn't it receive its addressing from the router?

In addition, with your desktop being assigned the public IP address, it is directly exposed to the Internet and possible malicious activity. You may want to take immediate steps to correct this and keep it behind the NAT of your router.

As far as the 255 attached devices seen by the Netgear utilities (software?), it's possible that it is seeing other modems/routers of other ISP customers. Can't tell for sure without a better idea of which side of the network this utility is scanning.