I'm trying to connect my Mac Pro tower (2020) to my network using ethernet but am experiencing problems if use my Netgear GS105 switch, this setup results in the MacPro saying "Cable connected but self-assigned IP". I've renewed DHCP leases, changed all sorts of settings including on my router but nothing works, I have also validated that this setup does work fine with every other computer (including a MacPro Trashcan) and if I connect the MacPro Cheese-grater directly to the router it works so to recap:

This does not work:


This does work:

[Router]--<cable_a>--[Switch]--<cable_b>--[MacPro Trashcan]

These also work:



I've also tried different cables in place of both <cable_a> and <cable_b> and it doesn't improve the situation, every possible combo works except if I have the MacPro 2020 Tower plugged in via the Netgear switch. Is there some issue with unmanaged switches and MacPro 2020 Towers?

  • 2
    Any differences between the MacPros at SysPrefs> Network> Ethernet> Advanced> Hardware? Or in ifconfig?
    – Gilby
    Apr 22, 2021 at 5:52
  • Good Q, it just says 'Automatically' under Hardware, same on both machines.
    – Shizam
    Apr 22, 2021 at 16:57
  • Hopefully it is correctly negotiating hardware settings between Mac and switch. What happens if you set the IP address manually? Choose an address outside the router's DHCP range, but within your subnet.
    – Gilby
    Apr 22, 2021 at 22:01

1 Answer 1


The problem in my case was the switch I was using was an "unmanaged" switch, I replaced it with a "managed" switch and my MacPro was able to use it just fine.

  • 1
    This makes no sense. A managed switch only allows you to configured it remotely, usually by a web interface. An un-managed switch just moves packets across ports. It is more likely that your switch was bad.
    – Allan
    Apr 18, 2023 at 3:41

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