Arduino ethernet not working behind a switch.

Projects Networking, Protocols, and Devices
1

Hello. I am new to the Arduino world and to this forum.

I'm trying to control my water heater in my house over the internet.
I use Arduino Uno, WIFI shield W5100 and a relay.
I'm controlling the device with the help of the nearbus.net, with the attached code.
This is working well, when connected with cable to my home modem\router.
But the water heater control is in my 2nd floor, which receives a cable from the router and uses a switch to distribute the ethernet in the 2nd floor.
When I connect the arduino after the switch I cannot communicate with it. Tried that with three different codes. One from your site that connects to google and reports if succeeded at the serial monitor.
On all of these codes the situation is the same. Working good without switch. Not working behind the switch.
The switch is Planet SW504.
I tried the neighbor's switch: Level One FSW0511. The result was OK. Working good behind the switch.
I bought a switch: Level One FSW0811, because the store did not have the 0511, and I thought it should work the same. Checked: Not good.

Do you have any Ideas?

Thanks.

Hanan.

Hello_World_Ether_hanan_upper_floor.ino (12.3 KB)

2

It would appear that your stated results have somewhat eliminated the arduino/W5100 as the problem. Have you tried a similar experiment but use say a laptop connected to the cable that the arduino/W5100 is normally connected to? The purpose would be to see if the switches behave the same way they did when you connected the arduino/W5100?

3

Hello, thank you for helping.
Yes, I did connect my laptop to the Arduino's Ethernet cable. It's working with all three switches with no problem.
I can also eliminate a cable problem, because if I just replace the 0811 with the 0511 then the Arduino works OK.
In the last day I'm working with the 0511 and it works every time. I agreed with my neighbor that we will replace our switches for good.
It is just weird.
Now I'm facing another problem: sometimes after a few minutes, and sometimes it takes few hours, but eventually I cannot access the Arduino anymore. It says "DOWN" in the nearbus website.
To fix that I need to manually reset the Arduino.
Thanks you.
Hanan.