Hi, sorry for the delay, I had just read your post and I could said "me too" But I solved the problem and it works for two years now. I explain my solution here, if the French don't afraid you. https://easydomoticz.com/forum/viewtopic.php?f=20&t=6497 I resume, a 7.5volts power supply, a passive injector, and a spécial home-made cable to bypass the RJ45 socket. The 7.5 v go to Vin-Gnd of the Nano to produce 5v wich is returned to the W5100. QED. Rpx.

RTF(T)roubleshoot-guide http://www.mysensors.org/build/debug

I use a cheap Chinese 5100 module together with the MQTT gateway and it is warm but have not measured any actual temperature. Works 24 hours a day (now for a couple of months). Most problems have been due to the MQTT code implementation itself . But for most "simple" sensors it runs OK with Openhab.

Original post is now updated (look at the bottom of it). (ping @bjornhallberg)

Sorry for the huge kick.. But I seem to have the same ethernet gateway as TS. His his wire diagram valid?

I have a similar problem. I upgraded from 1.3 to 1.4 and my Wiznet gateway does not work. I can ping version 1.3 from my PC and it see the gateway. When I ping 1.4 from my PC it says that the destination address can not be found. I have downloaded the latest Ethernet gateway sketch, but it did not help. Has any other file change that could effect this. Thanks John