Faulty ethernet shield?!

Hi !
I've been using an ethernet shield to send UDP value (temperature , humidty and weight) to my influxDB server.
Its a very simple code so i'm not going to bother posting it, pretty much sends 3 lines over UDP.

The problem is RANDOM, could be 8 hours, 10 hours even 4 hours, the ethernet shield will stop sending these UDP packets. It is definitely not the arduino as the arduino is still running its loop and sending serial. The TX light no longer blinks.

The way i can get it to work again is, 1 unplug all power or re-upload my code.

I've ruled out the code,
I've ruled out the power supply (using a buck, tried several voltages, using usb only etc).
I've ruled out heat by adding a heatsink to the ethernet shield and its warm, not hot.
It's definitely not influxDB.
I also added a plastic insulator between the ethernet shields RJ45 port and the Arduino USB (since they are really close).

Can someone steer me in the right direction of a good ethernet shield that will just WORK 24/7 and is reliable. The one i'm using is W5100 which i purchased maybe 5 years ago. This is driving me nuts. The reason why i can't just reset it all the time is because the weight sensor needs to TARE everytime it resets, therefore i have to lift my load off.

I use a w5100 shield and it works great with a Mega 2560 or a Due. I've run it for days at a time using UDP without a failure.

What OS are you running on the PC? I use Linux (Ubuntu) and have a C program that has been airtight, bulletproof.

Are you certain it isn't the PC code that is failing?

edit: Are you using error checking on the Arduino? Is the endPacket call returning fail?

Yes i'm pretty sure the code is VERY simple.
At the moment i'm using an arduino uno.
Anyway, can i ask which revision of arduino + ethernet shield you're using specifically?
Because my Arduino's were purchased years ago, same with my ethernet shield.
I know for a fact my Sainsmart Mega 2560 isn't compatible with my Ethernet shield (there were mods to make it work but i didnt want to do it).
Anyway i have purchased another 2560 hoping it's a newer revision that works.
No error checking. Using windows 10. But the problem is very random, the windows machine is fine, it's only a one way UDP communication.

I'm using an official ethernet shield R2, the version just prior to the newest I believe.

Are you sure it is the mega that is the problem? Early ethernet shields were not compatible with the Mega due to the lack of the ICSP pin connector on the shield.

Im pretty sure because I bought all my arduino gear 5+ years ago.
Using the same code etc.. it all works on the uno, but with the ethernet shield its not working on my old 2560.
There are a few threads about the 2560 where i needed to re-route the ICSP pins but i coulnd't be bothered because my wiring was already messy. I'm however, awaiting delivery of a newer (hopefully) version of the 2560 the revision 3. I also purchase another W5100 awaiting delivery ( those ones never had any revisions right?).

The problem is RANDOM, could be 8 hours, 10 hours even 4 hours, the ethernet shield will stop sending these UDP packets.

What about the IP address of the Ethernet shield?

Do you assign a fixed IP address to the Ethernet shield or do you obtain a dynamic IP address by DHCP?

I cannot see that as you are refusing to show the source code and strictly deny that the problem might reside in the code.