on my weather station project, i seem to have an issue where if the power fails, and comes back, it requires that i reset the board for the Ethernet shield to start up. i don't remember the brand or model Ethernet shield, only that it is off-brand, and i think W5200 chipset. i have ordered a new Arduino W5500 chipset Ethernet shield to see if it helps, but in case it doesn't solve the issue...
power supply is a PoE splitter from Adafruit that puts out a hair over 5Vdc, @ 2.5A.
code is here: WeatherStation/WeatherStation.ino at master · travis-farmer/WeatherStation · GitHub
really, i think it is the Ethernet shield, but if somebody else knows where the issue could be from... i am open to suggestion.
not a particularly great remote weather station if i have to go out and hit reset whenever the power fails. seems to work great otherwise.