Ethernet switch wreaking havoc on my network

[swwack91]

I'm going a bit crazy trying to solve this one, so maybe the MacRumors family can point me in the right direction...

Something is fishy with my network. I've recently added a 5-port unmanaged ethernet switch (TP-Link TL-SG105) to my network. When the switch is connected to my Verizon FiOS G1100 router, the ethernet devices attached directly to the G1100's ports cannot be reached.

Disconnecting the TL-SG105 from the G1100 solves the problem immediately.

The network has worked for a few hours at a time without issue but eventually the G1100's "local" devices end up unresponsive.

I realize this is a bit of an odd one, so I made a diagram to help:

https://imgur.com/a/LIcrMKm

Some things I've already tried:

• Different cables between the G1100 and TL-SG105 don't change the result.
• I used a cable tester on the cable connecting the G1100 and TL-SG105 and all is good.
• None of the devices on my network are running their own DHCP server.
• I've reached out to TP-Link's support and have not yet heard back but since it's an unmanaged switch, I think it's pretty benign.
• Wifi is entirely unaffected by this issue and continues to function even when the G1100's ethernet devices are not working.

My gut says it's something funny in the G1100's configuration.

Does anyone have any thoughts?

 

[LIVEFRMNYC]

Try reserving IP addresses for each device. Or it could be a double nat issue.

 

[satcomer]

Depend is Switch creating a subnet or NAT somehow? Do you still have the switch to tell you what it is doing?

 

[BrianBaughn]

Switches can go bad and thus presumably can be bad from the get-go. Try another one.